From 6ba413079f8c26a78372c086ff5068ff80a1c2ea Mon Sep 17 00:00:00 2001
From: Thomas D Ahle <thomas@ahle.dk>
Date: Sat, 2 Mar 2024 19:20:15 -0800
Subject: [PATCH 1/8] Some refinements to signature, allowing instantiation and
 fixing lint issues.

---
 dspy/signatures/signature.py       | 256 +++++++++++++++--------------
 pyproject.toml                     |  14 --
 tests/signatures/test_signature.py |  40 +++--
 3 files changed, 160 insertions(+), 150 deletions(-)

diff --git a/dspy/signatures/signature.py b/dspy/signatures/signature.py
index 7cd2f170cb..a335f219f0 100644
--- a/dspy/signatures/signature.py
+++ b/dspy/signatures/signature.py
@@ -3,37 +3,42 @@
 import dsp
 from pydantic import BaseModel, Field, create_model
 from pydantic.fields import FieldInfo
-from typing import Type, Union, Dict, Tuple
+from typing import Type, Union, Dict, Tuple  # noqa: UP035
 import re
 
 from dspy.signatures.field import InputField, OutputField, new_to_old_field
 
 
-def signature_to_template(signature):
-    """Convert from new to legacy format"""
+def signature_to_template(signature) -> dsp.Template:
+    """Convert from new to legacy format."""
     return dsp.Template(
         signature.instructions,
         **{name: new_to_old_field(field) for name, field in signature.fields.items()},
     )
 
 
-def _default_instructions(cls):
-    inputs_ = ", ".join([f"`{field}`" for field in cls.input_fields.keys()])
-    outputs_ = ", ".join([f"`{field}`" for field in cls.output_fields.keys()])
+def _default_instructions(cls) -> str:
+    inputs_ = ", ".join([f"`{field}`" for field in cls.input_fields])
+    outputs_ = ", ".join([f"`{field}`" for field in cls.output_fields])
     return f"Given the fields {inputs_}, produce the fields {outputs_}."
 
 
 class SignatureMeta(type(BaseModel)):
-    def __new__(mcs, name, bases, namespace, **kwargs):
+    def __call__(cls, *args, **kwargs):  # noqa: ANN002
+        if cls is Signature:
+            return make_signature(*args, **kwargs)
+        return super().__call__(*args, **kwargs)
+
+    def __new__(mcs, signature_name, bases, namespace, **kwargs):  # noqa: N804
         # Set `str` as the default type for all fields
         raw_annotations = namespace.get("__annotations__", {})
-        for name, field in namespace.items():
+        for name, _field in namespace.items():
             if not name.startswith("__") and name not in raw_annotations:
                 raw_annotations[name] = str
         namespace["__annotations__"] = raw_annotations
 
         # Let Pydantic do its thing
-        cls = super().__new__(mcs, name, bases, namespace, **kwargs)
+        cls = super().__new__(mcs, signature_name, bases, namespace, **kwargs)
 
         if cls.__doc__ is None:
             cls.__doc__ = _default_instructions(cls)
@@ -69,17 +74,20 @@ def signature(cls) -> str:
     def instructions(cls) -> str:
         return getattr(cls, "__doc__", "")
 
-    def with_instructions(cls, instructions: str):
+    def with_instructions(cls, instructions: str) -> Type["Signature"]:
         return Signature(cls.fields, instructions)
 
     @property
-    def fields(cls):
+    def fields(cls) -> dict[str, FieldInfo]:
         # Make sure to give input fields before output fields
         return {**cls.input_fields, **cls.output_fields}
 
-    def with_updated_fields(cls, name, type_=None, **kwargs):
-        """Returns a new Signature type with the field, name, updated
-        with fields[name].json_schema_extra[key] = value."""
+    def with_updated_fields(cls, name, type_=None, **kwargs) -> Type["Signature"]:
+        """Update the field, name, in a new Signature type.
+
+        Returns a new Signature type with the field, name, updated
+        with fields[name].json_schema_extra[key] = value.
+        """
         fields_copy = deepcopy(cls.fields)
         fields_copy[name].json_schema_extra = {
             **fields_copy[name].json_schema_extra,
@@ -90,27 +98,23 @@ def with_updated_fields(cls, name, type_=None, **kwargs):
         return Signature(fields_copy, cls.instructions)
 
     @property
-    def input_fields(cls):
+    def input_fields(cls) -> dict[str, FieldInfo]:
         return cls._get_fields_with_type("input")
 
     @property
-    def output_fields(cls):
+    def output_fields(cls) -> dict[str, FieldInfo]:
         return cls._get_fields_with_type("output")
 
-    def _get_fields_with_type(cls, field_type):
-        return {
-            k: v
-            for k, v in cls.model_fields.items()
-            if v.json_schema_extra["__dspy_field_type"] == field_type
-        }
+    def _get_fields_with_type(cls, field_type) -> dict[str, FieldInfo]:
+        return {k: v for k, v in cls.model_fields.items() if v.json_schema_extra["__dspy_field_type"] == field_type}
 
-    def prepend(cls, name, field, type_=None):
+    def prepend(cls, name, field, type_=None) -> Type["Signature"]:
         return cls.insert(0, name, field, type_)
 
-    def append(cls, name, field, type_=None):
+    def append(cls, name, field, type_=None) -> Type["Signature"]:
         return cls.insert(-1, name, field, type_)
 
-    def insert(cls, index: int, name: str, field, type_: Type = None):
+    def insert(cls, index: int, name: str, field, type_: Type = None) -> Type["Signature"]:
         # It's posisble to set the type as annotation=type in pydantic.Field(...)
         # But this may be annoying for users, so we allow them to pass the type
         if type_ is None:
@@ -122,11 +126,7 @@ def insert(cls, index: int, name: str, field, type_: Type = None):
         output_fields = list(cls.output_fields.items())
 
         # Choose the list to insert into based on the field type
-        lst = (
-            input_fields
-            if field.json_schema_extra["__dspy_field_type"] == "input"
-            else output_fields
-        )
+        lst = input_fields if field.json_schema_extra["__dspy_field_type"] == "input" else output_fields
         # We support negative insert indices
         if index < 0:
             index += len(lst) + 1
@@ -137,83 +137,7 @@ def insert(cls, index: int, name: str, field, type_: Type = None):
         new_fields = dict(input_fields + output_fields)
         return Signature(new_fields, cls.instructions)
 
-    def _parse_signature(cls, signature: str) -> Tuple[Type, Field]:
-        pattern = r"^\s*[\w\s,]+\s*->\s*[\w\s,]+\s*$"
-        if not re.match(pattern, signature):
-            raise ValueError(f"Invalid signature format: '{signature}'")
-
-        fields = {}
-        inputs_str, outputs_str = map(str.strip, signature.split("->"))
-        inputs = [v.strip() for v in inputs_str.split(",") if v.strip()]
-        outputs = [v.strip() for v in outputs_str.split(",") if v.strip()]
-        for name in inputs:
-            fields[name] = (str, InputField())
-        for name in outputs:
-            fields[name] = (str, OutputField())
-
-        return fields
-
-    def __call__(
-        cls,
-        signature: Union[str, Dict[str, Tuple[type, FieldInfo]]],
-        instructions: str = None,
-    ):
-        """
-        Creates a new Signature type with the given fields and instructions.
-        Note:
-            Even though we're calling a type, we're not making an instance of the type.
-            In general we don't allow instances of Signature types to be made. The call
-            syntax is only for your convenience.
-        Parameters:
-            signature: Format: "input1, input2 -> output1, output2"
-            instructions: Optional prompt for the signature.
-        """
-
-        if isinstance(signature, str):
-            fields = cls._parse_signature(signature)
-        else:
-            fields = signature
-
-        # Validate the fields, this is important because we sometimes forget the
-        # slightly unintuitive syntax with tuples of (type, Field)
-        fixed_fields = {}
-        for name, type_field in fields.items():
-            assert isinstance(
-                name, str,
-            ), f"Field names must be strings, not {type(name)}"
-            if isinstance(type_field, FieldInfo):
-                type_ = type_field.annotation
-                field = type_field
-            else:
-                assert isinstance(
-                    type_field, tuple,
-                ), f"Field values must be tuples, not {type(type_field)}"
-                type_, field = type_field
-            # It might be better to be explicit about the type, but it currently would break
-            # program of thought and teleprompters, so we just silently default to string.
-            if type_ is None:
-                type_ = str
-            assert isinstance(type_, type) or isinstance(
-                typing.get_origin(type_), type,
-            ), f"Field types must be types, not {type(type_)}"
-            assert isinstance(
-                field, FieldInfo,
-            ), f"Field values must be Field instances, not {type(field)}"
-            fixed_fields[name] = (type_, field)
-
-        # Fixing the fields shouldn't change the order
-        assert list(fixed_fields.keys()) == list(fields.keys())
-
-        # Default prompt when no instructions are provided
-        if instructions is None:
-            sig = Signature(signature, "")  # Simple way to parse input/output fields
-            instructions = _default_instructions(sig)
-
-        signature = create_model("Signature", __base__=Signature, **fixed_fields)
-        signature.__doc__ = instructions
-        return signature
-
-    def equals(cls, other):
+    def equals(cls, other) -> bool:
         """Compare the JSON schema of two Pydantic models."""
         if not isinstance(other, type) or not issubclass(other, BaseModel):
             return False
@@ -226,30 +150,44 @@ def equals(cls, other):
         return True
 
     def __repr__(cls):
-        """
-        Outputs something on the form:
+        """Output a representation of the signature.
+
+        Uses the form:
         Signature(question, context -> answer
             question: str = InputField(desc="..."),
             context: List[str] = InputField(desc="..."),
             answer: int = OutputField(desc="..."),
-        )
+        ).
         """
         field_reprs = []
         for name, field in cls.fields.items():
             field_reprs.append(f"{name} = Field({field})")
         field_repr = "\n    ".join(field_reprs)
-        return (
-            f"Signature({cls.signature}\n"
-            f"    instructions={repr(cls.instructions)}\n"
-            f"    {field_repr}\n)"
-        )
+        return f"{cls.__name__}({cls.signature}\n    instructions={repr(cls.instructions)}\n    {field_repr}\n)"
 
 
 class Signature(BaseModel, metaclass=SignatureMeta):
+    """A signature for a predictor.
+
+    You typically subclass it, like this:
+    class MySignature(Signature):
+        input: str = InputField(desc="...")
+        output: int = OutputField(desc="...")
+
+    You can call Signature("input1, input2 -> output1, output2") to create a new signature type.
+    You can also include instructions, Signature("input -> output", "This is a test").
+    But it's generally better to use the make_signature function.
+
+    If you are not sure if your input is a string representation, (like "input1, input2 -> output1, output2"),
+    or a signature, you can use the ensure_signature function.
+
+    For compatibility with the legacy dsp format, you can use the signature_to_template function.
+    """
+
     pass
 
 
-def ensure_signature(signature):
+def ensure_signature(signature: str | Type[Signature]) -> Signature:
     if signature is None:
         return None
     if isinstance(signature, str):
@@ -257,19 +195,97 @@ def ensure_signature(signature):
     return signature
 
 
-def infer_prefix(attribute_name: str) -> str:
-    """Infers a prefix from an attribute name."""
+def make_signature(
+    signature: Union[str, Dict[str, Tuple[type, FieldInfo]]],
+    instructions: str = None,
+    signature_name: str = "StringSignature",
+) -> Type[Signature]:
+    """Create a new Signature type with the given fields and instructions.
+
+    Note:
+        Even though we're calling a type, we're not making an instance of the type.
+        In general, instances of Signature types are not allowed to be made. The call
+        syntax is provided for convenience.
+
+    Args:
+        signature: The signature format, specified as "input1, input2 -> output1, output2".
+        instructions: An optional prompt for the signature.
+        signature_name: An optional name for the new signature type.
+    """
+    fields = _parse_signature(signature) if isinstance(signature, str) else signature
+
+    # Validate the fields, this is important because we sometimes forget the
+    # slightly unintuitive syntax with tuples of (type, Field)
+    fixed_fields = {}
+    for name, type_field in fields.items():
+        if not isinstance(name, str):
+            raise ValueError(f"Field names must be strings, not {type(name)}")
+        if isinstance(type_field, FieldInfo):
+            type_ = type_field.annotation
+            field = type_field
+        else:
+            if not isinstance(type_field, tuple):
+                raise ValueError(f"Field values must be tuples, not {type(type_field)}")
+            type_, field = type_field
+        # It might be better to be explicit about the type, but it currently would break
+        # program of thought and teleprompters, so we just silently default to string.
+        if type_ is None:
+            type_ = str
+        if not isinstance(type_, type) and not isinstance(typing.get_origin(type_), type):
+            raise ValueError(f"Field types must be types, not {type(type_)}")
+        if not isinstance(field, FieldInfo):
+            raise ValueError(f"Field values must be Field instances, not {type(field)}")
+        fixed_fields[name] = (type_, field)
+
+    # Fixing the fields shouldn't change the order
+    assert list(fixed_fields.keys()) == list(fields.keys())  # noqa: S101
+
+    # Default prompt when no instructions are provided
+    if instructions is None:
+        sig = Signature(signature, "")  # Simple way to parse input/output fields
+        instructions = _default_instructions(sig)
+
+    return create_model(
+        signature_name,
+        __base__=Signature,
+        __doc__=instructions,
+        **fixed_fields,
+    )
 
+
+def _parse_signature(signature: str) -> Tuple[Type, Field]:
+    pattern = r"^\s*[\w\s,]+\s*->\s*[\w\s,]+\s*$"
+    if not re.match(pattern, signature):
+        raise ValueError(f"Invalid signature format: '{signature}'")
+
+    fields = {}
+    inputs_str, outputs_str = map(str.strip, signature.split("->"))
+    inputs = [v.strip() for v in inputs_str.split(",") if v.strip()]
+    outputs = [v.strip() for v in outputs_str.split(",") if v.strip()]
+    for name in inputs:
+        fields[name] = (str, InputField())
+    for name in outputs:
+        fields[name] = (str, OutputField())
+
+    return fields
+
+
+def infer_prefix(attribute_name: str) -> str:
+    """Infer a prefix from an attribute name."""
     # Convert camelCase to snake_case, but handle sequences of capital letters properly
     s1 = re.sub("(.)([A-Z][a-z]+)", r"\1_\2", attribute_name)
     intermediate_name = re.sub("([a-z0-9])([A-Z])", r"\1_\2", s1)
 
     # Insert underscores around numbers to ensure spaces in the final output
     with_underscores_around_numbers = re.sub(
-        r"([a-zA-Z])(\d)", r"\1_\2", intermediate_name,
+        r"([a-zA-Z])(\d)",
+        r"\1_\2",
+        intermediate_name,
     )
     with_underscores_around_numbers = re.sub(
-        r"(\d)([a-zA-Z])", r"\1_\2", with_underscores_around_numbers,
+        r"(\d)([a-zA-Z])",
+        r"\1_\2",
+        with_underscores_around_numbers,
     )
 
     # Convert snake_case to 'Proper Title Case', but ensure acronyms are uppercased
diff --git a/pyproject.toml b/pyproject.toml
index bdb4bc75d9..7828de0cf3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -232,28 +232,14 @@ ignore = [
     "ANN003",
     # utf-8 encoding skip
     "UP009",
-    # First argument of a method should be named `self`
-    "N805",
-    # 1 blank line required between summary line and description
-    "D205",
     # Missing return type annotation for special method `__init__`
     "ANN204",
-    # Avoid using the generic variable name `df` for DataFrames
-    "PD901",
-    # Unnecessary assignment to `df` before `return` statement
-    "RET504",
-    # commented code
-    "ERA001",
     # Star-arg unpacking after a keyword argument is strongly discouraged
     "B026",
     # Missing type annotation for function argument `self`
     "ANN001",
     # Dynamically typed expressions (typing.Any) are disallowed in `wrapper`
     "ANN401",
-    # Unnecessary `elif` after `return` statement
-    "RET505",
-    # Within an `except` clause, raise exceptions with `raise
-    "B904",
     # We don't need docstrings for every method
     "ANN202",
     "D107",
diff --git a/tests/signatures/test_signature.py b/tests/signatures/test_signature.py
index b093258540..26fdfc7aa0 100644
--- a/tests/signatures/test_signature.py
+++ b/tests/signatures/test_signature.py
@@ -39,12 +39,8 @@ class TestSignature(Signature):
         input = InputField(prefix="Modified:")
         output = OutputField()
 
-    assert (
-        TestSignature.input_fields["input"].json_schema_extra["prefix"] == "Modified:"
-    )
-    assert (
-        TestSignature.output_fields["output"].json_schema_extra["prefix"] == "Output:"
-    )
+    assert TestSignature.input_fields["input"].json_schema_extra["prefix"] == "Modified:"
+    assert TestSignature.output_fields["output"].json_schema_extra["prefix"] == "Output:"
 
 
 def test_signature_parsing():
@@ -69,10 +65,7 @@ def test_with_updated_field():
     assert signature1 is not signature2, "The type should be immutable"
     for key in signature1.fields.keys():
         if key != "input1":
-            assert (
-                signature1.fields[key].json_schema_extra
-                == signature2.fields[key].json_schema_extra
-            )
+            assert signature1.fields[key].json_schema_extra == signature2.fields[key].json_schema_extra
     assert signature1.instructions == signature2.instructions
 
 
@@ -97,18 +90,14 @@ def test_signature_instructions_none():
 
 
 def test_signature_from_dict():
-    signature = Signature(
-        {"input1": InputField(), "input2": InputField(), "output": OutputField()}
-    )
+    signature = Signature({"input1": InputField(), "input2": InputField(), "output": OutputField()})
     for k in ["input1", "input2", "output"]:
         assert k in signature.fields
         assert signature.fields[k].annotation == str
 
 
 def test_signature_from_dict():
-    signature = Signature(
-        {"input1": InputField(), "input2": InputField(), "output": OutputField()}
-    )
+    signature = Signature({"input1": InputField(), "input2": InputField(), "output": OutputField()})
     assert "input1" in signature.input_fields
     assert "input2" in signature.input_fields
     assert "output" in signature.output_fields
@@ -164,3 +153,22 @@ def test_infer_prefix():
     assert infer_prefix("URLAddress") == "URL Address"
     assert infer_prefix("isHTTPSecure") == "Is HTTP Secure"
     assert infer_prefix("isHTTPSSecure123") == "Is HTTPS Secure 123"
+
+
+def test_insantiating():
+    sig = Signature("input -> output")
+    assert issubclass(sig, Signature)
+    assert sig.__name__ == "StringSignature"
+    value = sig(input="test", output="test")
+    assert isinstance(value, sig)
+
+
+def test_insantiating2():
+    class SubSignature(Signature):
+        input = InputField()
+        output = OutputField()
+
+    assert issubclass(SubSignature, Signature)
+    assert SubSignature.__name__ == "SubSignature"
+    value = SubSignature(input="test", output="test")
+    assert isinstance(value, SubSignature)

From 6af5366e9064918e784f68ed736626e08c53a317 Mon Sep 17 00:00:00 2001
From: Thomas D Ahle <thomas@ahle.dk>
Date: Sat, 2 Mar 2024 19:23:47 -0800
Subject: [PATCH 2/8] Avoid shadowing by lint

---
 pyproject.toml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pyproject.toml b/pyproject.toml
index 7828de0cf3..db7fc3fe4f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -218,6 +218,8 @@ select = [
     "ERA",
     # pandas-vet
     "PD",
+    # avoid shadowing
+    "PLW",
 ]
 ignore = [
     "D100",

From 9a1c189171b774f590e17254758cfe166294cb89 Mon Sep 17 00:00:00 2001
From: Thomas D Ahle <thomas@ahle.dk>
Date: Sun, 3 Mar 2024 12:30:25 -0800
Subject: [PATCH 3/8] Support for n=... and type-strings

---
 dspy/functional/functional.py       | 61 ++++++++++++++++-------------
 dspy/primitives/prediction.py       | 20 +++++-----
 dspy/signatures/signature.py        | 53 ++++++++++++++++++++++---
 tests/functional/test_functional.py | 51 ++++++++++++++++++------
 4 files changed, 130 insertions(+), 55 deletions(-)

diff --git a/dspy/functional/functional.py b/dspy/functional/functional.py
index 96c218ebbd..041ee7abc5 100644
--- a/dspy/functional/functional.py
+++ b/dspy/functional/functional.py
@@ -1,3 +1,4 @@
+from collections import defaultdict
 import inspect
 import os
 import openai
@@ -7,6 +8,7 @@
 from typing import Annotated, List, Tuple  # noqa: UP035
 from dsp.templates import passages2text
 import json
+from dspy.primitives.prediction import Prediction
 
 from dspy.signatures.signature import ensure_signature
 
@@ -71,7 +73,7 @@ def TypedChainOfThought(signature) -> dspy.Module:  # noqa: N802
 class TypedPredictor(dspy.Module):
     def __init__(self, signature):
         super().__init__()
-        self.signature = signature
+        self.signature = ensure_signature(signature)
         self.predictor = dspy.Predict(signature)
 
     def copy(self) -> "TypedPredictor":
@@ -127,8 +129,7 @@ def _prepare_signature(self) -> dspy.Signature:
                         name,
                         desc=field.json_schema_extra.get("desc", "")
                         + (
-                            ". Respond with a single JSON object. JSON Schema: "
-                            + json.dumps(type_.model_json_schema())
+                            ". Respond with a single JSON object. JSON Schema: " + json.dumps(type_.model_json_schema())
                         ),
                         format=lambda x, to_json=to_json: (x if isinstance(x, str) else to_json(x)),
                         parser=lambda x, from_json=from_json: from_json(_unwrap_json(x)),
@@ -152,28 +153,33 @@ def forward(self, **kwargs) -> dspy.Prediction:
         for try_i in range(MAX_RETRIES):
             result = self.predictor(**modified_kwargs, new_signature=signature)
             errors = {}
-            parsed_results = {}
+            parsed_results = defaultdict(list)
             # Parse the outputs
             for name, field in signature.output_fields.items():
-                try:
-                    value = getattr(result, name)
-                    parser = field.json_schema_extra.get("parser", lambda x: x)
-                    parsed_results[name] = parser(value)
-                except (pydantic.ValidationError, ValueError) as e:
-                    errors[name] = _format_error(e)
-                    # If we can, we add an example to the error message
-                    current_desc = field.json_schema_extra.get("desc", "")
-                    i = current_desc.find("JSON Schema: ")
-                    if i == -1:
-                        continue  # Only add examples to JSON objects
-                    suffix, current_desc = current_desc[i:], current_desc[:i]
-                    prefix = "You MUST use this format: "
-                    if try_i + 1 < MAX_RETRIES \
-                            and prefix not in current_desc \
-                            and (example := self._make_example(field.annotation)):
-                        signature = signature.with_updated_fields(
-                            name, desc=current_desc + "\n" + prefix + example + "\n" + suffix,
-                        )
+                for i, completion in enumerate(result.completions):
+                    try:
+                        value = completion[name]
+                        parser = field.json_schema_extra.get("parser", lambda x: x)
+                        completion[name] = parser(value)
+                        parsed_results[name].append(parser(value))
+                    except (pydantic.ValidationError, ValueError) as e:
+                        errors[name] = _format_error(e)
+                        # If we can, we add an example to the error message
+                        current_desc = field.json_schema_extra.get("desc", "")
+                        i = current_desc.find("JSON Schema: ")
+                        if i == -1:
+                            continue  # Only add examples to JSON objects
+                        suffix, current_desc = current_desc[i:], current_desc[:i]
+                        prefix = "You MUST use this format: "
+                        if (
+                            try_i + 1 < MAX_RETRIES
+                            and prefix not in current_desc
+                            and (example := self._make_example(field.annotation))
+                        ):
+                            signature = signature.with_updated_fields(
+                                name,
+                                desc=current_desc + "\n" + prefix + example + "\n" + suffix,
+                            )
             if errors:
                 # Add new fields for each error
                 for name, error in errors.items():
@@ -187,11 +193,12 @@ def forward(self, **kwargs) -> dspy.Prediction:
                     )
             else:
                 # If there are no errors, we return the parsed results
-                for name, value in parsed_results.items():
-                    setattr(result, name, value)
-                return result
+                # for name, value in parsed_results.items():
+                #    setattr(result, name, value)
+                return Prediction.from_completions(parsed_results)
         raise ValueError(
-            "Too many retries trying to get the correct output format. " + "Try simplifying the requirements.", errors,
+            "Too many retries trying to get the correct output format. " + "Try simplifying the requirements.",
+            errors,
         )
 
 
diff --git a/dspy/primitives/prediction.py b/dspy/primitives/prediction.py
index df653c1c4a..d77ee15a9d 100644
--- a/dspy/primitives/prediction.py
+++ b/dspy/primitives/prediction.py
@@ -4,12 +4,12 @@
 class Prediction(Example):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
-        
+
         del self._demos
         del self._input_keys
 
         self._completions = None
-    
+
     @classmethod
     def from_completions(cls, list_or_dict, signature=None):
         obj = cls()
@@ -17,16 +17,16 @@ def from_completions(cls, list_or_dict, signature=None):
         obj._store = {k: v[0] for k, v in obj._completions.items()}
 
         return obj
-    
+
     def __repr__(self):
-        store_repr = ',\n    '.join(f"{k}={repr(v)}" for k, v in self._store.items())
+        store_repr = ",\n    ".join(f"{k}={repr(v)}" for k, v in self._store.items())
 
         if self._completions is None or len(self._completions) == 1:
             return f"Prediction(\n    {store_repr}\n)"
-        
+
         num_completions = len(self._completions)
         return f"Prediction(\n    {store_repr},\n    completions=Completions(...)\n) ({num_completions-1} completions omitted)"
-        
+
     def __str__(self):
         return self.__repr__()
 
@@ -62,15 +62,15 @@ def __getitem__(self, key):
         if isinstance(key, int):
             if key < 0 or key >= len(self):
                 raise IndexError("Index out of range")
-            
+
             return Prediction(**{k: v[key] for k, v in self._completions.items()})
-        
+
         return self._completions[key]
 
     def __getattr__(self, name):
         if name in self._completions:
             return self._completions[name]
-        
+
         raise AttributeError(f"'{type(self).__name__}' object has no attribute '{name}'")
 
     def __len__(self):
@@ -82,7 +82,7 @@ def __contains__(self, key):
         return key in self._completions
 
     def __repr__(self):
-        items_repr = ',\n    '.join(f"{k}={repr(v)}" for k, v in self._completions.items())
+        items_repr = ",\n    ".join(f"{k}={repr(v)}" for k, v in self._completions.items())
         return f"Completions(\n    {items_repr}\n)"
 
     def __str__(self):
diff --git a/dspy/signatures/signature.py b/dspy/signatures/signature.py
index a335f219f0..95455c3704 100644
--- a/dspy/signatures/signature.py
+++ b/dspy/signatures/signature.py
@@ -1,9 +1,10 @@
+import ast
 from copy import deepcopy
 import typing
 import dsp
 from pydantic import BaseModel, Field, create_model
 from pydantic.fields import FieldInfo
-from typing import Type, Union, Dict, Tuple  # noqa: UP035
+from typing import Any, Type, Union, Dict, Tuple  # noqa: UP035
 import re
 
 from dspy.signatures.field import InputField, OutputField, new_to_old_field
@@ -254,7 +255,7 @@ def make_signature(
 
 
 def _parse_signature(signature: str) -> Tuple[Type, Field]:
-    pattern = r"^\s*[\w\s,]+\s*->\s*[\w\s,]+\s*$"
+    pattern = r"^\s*[\w\s,:]+\s*->\s*[\w\s,:]+\s*$"
     if not re.match(pattern, signature):
         raise ValueError(f"Invalid signature format: '{signature}'")
 
@@ -262,14 +263,54 @@ def _parse_signature(signature: str) -> Tuple[Type, Field]:
     inputs_str, outputs_str = map(str.strip, signature.split("->"))
     inputs = [v.strip() for v in inputs_str.split(",") if v.strip()]
     outputs = [v.strip() for v in outputs_str.split(",") if v.strip()]
-    for name in inputs:
-        fields[name] = (str, InputField())
-    for name in outputs:
-        fields[name] = (str, OutputField())
+    for name_type in inputs:
+        name, type_ = _parse_named_type_node(name_type)
+        fields[name] = (type_, InputField())
+    for name_type in outputs:
+        name, type_ = _parse_named_type_node(name_type)
+        fields[name] = (type_, OutputField())
 
     return fields
 
 
+def _parse_named_type_node(node, names=None) -> Any:
+    parts = node.split(":")
+    if len(parts) == 1:
+        return parts[0], str
+    name, type_str = parts
+    type_ = _parse_type_node(ast.parse(type_str), names)
+    return name, type_
+
+
+def _parse_type_node(node, names=None) -> Any:
+    """Recursively parse an AST node representing a type annotation.
+
+    using structural pattern matching introduced in Python 3.10.
+    """
+    if names is None:
+        names = {}
+    match node:
+        case ast.Module(body=body):
+            if len(body) != 1:
+                raise ValueError(f"Code is not syntactically valid: {node}")
+            return _parse_type_node(body[0], names)
+        case ast.Expr(value=value):
+            return _parse_type_node(value, names)
+        case ast.Name(id=id):
+            if id in names:
+                return names[id]
+            for type_ in [int, str, float, bool, list, tuple, dict]:
+                if type_.__name__ == id:
+                    return type_
+        case ast.Subscript(value=value, slice=slice):
+            base_type = _parse_type_node(value, names)
+            arg_type = _parse_type_node(slice, names)
+            return base_type[arg_type]
+        case ast.Tuple(elts=elts):
+            return tuple(_parse_type_node(elt, names) for elt in elts)
+    raise ValueError(f"Code is not syntactically valid: {node}")
+
+
 def infer_prefix(attribute_name: str) -> str:
     """Infer a prefix from an attribute name."""
     # Convert camelCase to snake_case, but handle sequences of capital letters properly
diff --git a/tests/functional/test_functional.py b/tests/functional/test_functional.py
index f515f93266..029519bcfd 100644
--- a/tests/functional/test_functional.py
+++ b/tests/functional/test_functional.py
@@ -35,9 +35,7 @@ def hard_questions(topics: List[str]) -> List[str]:
         pass
 
     expected = ["What is the speed of light?", "What is the speed of sound?"]
-    lm = DummyLM(
-        ['{"value": ["What is the speed of light?", "What is the speed of sound?"]}']
-    )
+    lm = DummyLM(['{"value": ["What is the speed of light?", "What is the speed of sound?"]}'])
     dspy.settings.configure(lm=lm)
 
     question = hard_questions(topics=["Physics", "Music"])
@@ -88,9 +86,7 @@ def test_simple_class():
     class Answer(pydantic.BaseModel):
         value: float
         certainty: float
-        comments: List[str] = pydantic.Field(
-            description="At least two comments about the answer"
-        )
+        comments: List[str] = pydantic.Field(description="At least two comments about the answer")
 
     class QA(FunctionalModule):
         @predictor
@@ -229,9 +225,7 @@ def simple_metric(example, prediction, trace=None):
     lm = DummyLM(["blue", "Ring-ding-ding-ding-dingeringeding!"], follow_examples=True)
     dspy.settings.configure(lm=lm, trace=[])
 
-    bootstrap = BootstrapFewShot(
-        metric=simple_metric, max_bootstrapped_demos=1, max_labeled_demos=1
-    )
+    bootstrap = BootstrapFewShot(metric=simple_metric, max_bootstrapped_demos=1, max_labeled_demos=1)
     compiled_student = bootstrap.compile(student, teacher=teacher, trainset=trainset)
 
     lm.inspect_history(n=2)
@@ -295,7 +289,7 @@ def flight_information(email: str) -> TravelInformation:
             # Example with a bad origin code.
             '{"origin": "JF0", "destination": "LAX", "date": "2022-12-25"}',
             # Example to help the model understand
-            '{...}',
+            "{...}",
             # Fixed
             '{"origin": "JFK", "destination": "LAX", "date": "2022-12-25"}',
         ]
@@ -344,9 +338,9 @@ def flight_information(email: str) -> TravelInformation:
         [
             # First origin is wrong, then destination, then all is good
             '{"origin": "JF0", "destination": "LAX", "date": "2022-12-25"}',
-            '{...}', # Example to help the model understand
+            "{...}",  # Example to help the model understand
             '{"origin": "JFK", "destination": "LA0", "date": "2022-12-25"}',
-            '{...}', # Example to help the model understand
+            "{...}",  # Example to help the model understand
             '{"origin": "JFK", "destination": "LAX", "date": "2022-12-25"}',
         ]
     )
@@ -447,3 +441,36 @@ def test(input: Annotated[str, Field(description="description")]) -> Annotated[f
     output = test(input="input")
 
     assert output == 0.5
+
+
+def test_multiple_outputs():
+    lm = DummyLM([str(i) for i in range(100)])
+    dspy.settings.configure(lm=lm)
+
+    test = TypedPredictor("input -> output")
+    output = test(input="input", config=dict(n=3)).completions.output
+    assert output == ["0", "1", "2"]
+
+
+def test_multiple_outputs_int():
+    lm = DummyLM([str(i) for i in range(100)])
+    dspy.settings.configure(lm=lm)
+
+    class TestSignature(dspy.Signature):
+        input: int = dspy.InputField()
+        output: int = dspy.OutputField()
+
+    test = TypedPredictor(TestSignature)
+
+    output = test(input=8, config=dict(n=3)).completions.output
+    assert output == [0, 1, 2]
+
+
+def test_parse_type_string():
+    lm = DummyLM([str(i) for i in range(100)])
+    dspy.settings.configure(lm=lm)
+
+    test = TypedPredictor("input:int -> output:int")
+
+    output = test(input=8, config=dict(n=3)).completions.output
+    assert output == [0, 1, 2]

From a021bd26763a0c3efa8fffa84e8a8fcdf27554f8 Mon Sep 17 00:00:00 2001
From: Thomas D Ahle <thomas@ahle.dk>
Date: Sun, 3 Mar 2024 12:30:35 -0800
Subject: [PATCH 4/8] Linting of dummy

---
 dspy/utils/dummies.py | 62 ++++++++++++++++++++++---------------------
 1 file changed, 32 insertions(+), 30 deletions(-)

diff --git a/dspy/utils/dummies.py b/dspy/utils/dummies.py
index a0c997145b..3a37388073 100644
--- a/dspy/utils/dummies.py
+++ b/dspy/utils/dummies.py
@@ -1,6 +1,5 @@
 import random
 from dsp.modules import LM
-from typing import List, Union, Dict
 import numpy as np
 from dsp.utils.utils import dotdict
 import re
@@ -9,9 +8,9 @@
 class DummyLM(LM):
     """Dummy language model for unit testing purposes."""
 
-    def __init__(self, answers: Union[List[str], Dict[str,str]], follow_examples: bool = False):
-        """
-        Initializes the dummy language model.
+    def __init__(self, answers: list[str] | dict[str, str], follow_examples: bool = False):
+        """Initializes the dummy language model.
+
         Parameters:
         - answers: A list of strings or a dictionary with string keys and values.
         - follow_examples: If True, and the prompt contains an example exactly equal to the prompt,
@@ -24,7 +23,7 @@ def __init__(self, answers: Union[List[str], Dict[str,str]], follow_examples: bo
         self.answers = answers
         self.follow_examples = follow_examples
 
-    def basic_request(self, prompt, n=1, **kwargs):
+    def basic_request(self, prompt, n=1, **kwargs) -> dict[str, list[dict[str, str]]]:
         """Generates a dummy response based on the prompt."""
         dummy_response = {"choices": []}
         for _ in range(n):
@@ -55,12 +54,14 @@ def basic_request(self, prompt, n=1, **kwargs):
                 answer = "No more responses"
 
             # Mimic the structure of a real language model response.
-            dummy_response["choices"].append({
-                "text": answer,
-                "finish_reason": "simulated completion",
-            })
-            
-            RED, GREEN, RESET = '\033[91m', '\033[92m', '\033[0m'
+            dummy_response["choices"].append(
+                {
+                    "text": answer,
+                    "finish_reason": "simulated completion",
+                },
+            )
+
+            RED, GREEN, RESET = "\033[91m", "\033[92m", "\033[0m"
             print("=== DummyLM ===")
             print(prompt, end="")
             print(f"{RED}{answer}{RESET}")
@@ -77,67 +78,68 @@ def basic_request(self, prompt, n=1, **kwargs):
 
         return dummy_response
 
-    def __call__(self, prompt, only_completed=True, return_sorted=False, **kwargs):
+    def __call__(self, prompt, _only_completed=True, _return_sorted=False, **kwargs):
         """Retrieves dummy completions."""
         response = self.basic_request(prompt, **kwargs)
         choices = response["choices"]
 
         # Filter choices and return text completions.
-        completions = [choice["text"] for choice in choices]
-
-        return completions
+        return [choice["text"] for choice in choices]
 
-    def get_convo(self, index):
-        """Get the prompt + anwer from the ith message"""
-        return self.history[index]['prompt'] \
-            + " " \
-            + self.history[index]['response']['choices'][0]['text']
+    def get_convo(self, index) -> str:
+        """Get the prompt + anwer from the ith message."""
+        return self.history[index]["prompt"] + " " + self.history[index]["response"]["choices"][0]["text"]
 
 
-def dummy_rm(passages=()):
+def dummy_rm(passages=()) -> callable:
     if not passages:
-        def inner(query:str, *, k:int, **kwargs):
+
+        def inner(query: str, *, k: int, **kwargs):
             assert False, "No passages defined"
+
         return inner
     max_length = max(map(len, passages)) + 100
     vectorizer = DummyVectorizer(max_length)
     passage_vecs = vectorizer(passages)
-    def inner(query:str, *, k:int, **kwargs):
+
+    def inner(query: str, *, k: int, **kwargs):
         assert k <= len(passages)
         query_vec = vectorizer([query])[0]
         scores = passage_vecs @ query_vec
         largest_idx = (-scores).argsort()[:k]
-        #return dspy.Prediction(passages=[passages[i] for i in largest_idx])
+        # return dspy.Prediction(passages=[passages[i] for i in largest_idx])
         return [dotdict(dict(long_text=passages[i])) for i in largest_idx]
+
     return inner
 
 
 class DummyVectorizer:
-    """Simple vectorizer based on n-grams"""
+    """Simple vectorizer based on n-grams."""
+
     def __init__(self, max_length=100, n_gram=2):
         self.max_length = max_length
         self.n_gram = n_gram
         self.P = 10**9 + 7  # A large prime number
         random.seed(123)
         self.coeffs = [random.randrange(1, self.P) for _ in range(n_gram)]
-    
+
     def _hash(self, gram):
-        """Hashes a string using a polynomial hash function"""
+        """Hashes a string using a polynomial hash function."""
         h = 1
         for coeff, c in zip(self.coeffs, gram):
             h = h * coeff + ord(c)
             h %= self.P
         return h % self.max_length
 
-    def __call__(self, texts: List[str]) -> np.ndarray:
+    def __call__(self, texts: list[str]) -> np.ndarray:
         vecs = []
         for text in texts:
-            grams = [text[i:i+self.n_gram] for i in range(len(text) - self.n_gram + 1)]
+            grams = [text[i : i + self.n_gram] for i in range(len(text) - self.n_gram + 1)]
             vec = [0] * self.max_length
             for gram in grams:
                 vec[self._hash(gram)] += 1
             vecs.append(vec)
-        
+
         vecs = np.array(vecs, dtype=np.float32)
         vecs -= np.mean(vecs, axis=1, keepdims=True)
         vecs /= np.linalg.norm(vecs, axis=1, keepdims=True) + 1e-10  # Added epsilon to avoid division by zero

From f223579a7e124c1e8b5ad27910f6a05190cd6433 Mon Sep 17 00:00:00 2001
From: Thomas D Ahle <thomas@ahle.dk>
Date: Sun, 3 Mar 2024 13:08:30 -0800
Subject: [PATCH 5/8] Rewrote type parsing to be 3.9 compatible

---
 dspy/signatures/signature.py | 49 +++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 20 deletions(-)

diff --git a/dspy/signatures/signature.py b/dspy/signatures/signature.py
index 95455c3704..6493a8ce19 100644
--- a/dspy/signatures/signature.py
+++ b/dspy/signatures/signature.py
@@ -285,29 +285,38 @@ def _parse_named_type_node(node, names=None) -> Any:
 def _parse_type_node(node, names=None) -> Any:
     """Recursively parse an AST node representing a type annotation.
 
-    using structural pattern matching introduced in Python 3.10.
+    without using structural pattern matching introduced in Python 3.10.
     """
     if names is None:
         names = {}
-    match node:
-        case ast.Module(body=body):
-            if len(body) != 1:
-                raise ValueError(f"Code is not syntactically valid: {node}")
-            return _parse_type_node(body[0], names)
-        case ast.Expr(value=value):
-            return _parse_type_node(value, names)
-        case ast.Name(id=id):
-            if id in names:
-                return names[id]
-            for type_ in [int, str, float, bool, list, tuple, dict]:
-                if type_.__name__ == id:
-                    return type_
-        case ast.Subscript(value=value, slice=slice):
-            base_type = _parse_type_node(value, names)
-            arg_type = _parse_type_node(slice, names)
-            return base_type[arg_type]
-        case ast.Tuple(elts=elts):
-            return tuple(_parse_type_node(elt, names) for elt in elts)
+
+    if isinstance(node, ast.Module):
+        body = node.body
+        if len(body) != 1:
+            raise ValueError(f"Code is not syntactically valid: {node}")
+        return _parse_type_node(body[0], names)
+
+    if isinstance(node, ast.Expr):
+        value = node.value
+        return _parse_type_node(value, names)
+
+    if isinstance(node, ast.Name):
+        id_ = node.id
+        if id_ in names:
+            return names[id_]
+        for type_ in [int, str, float, bool, list, tuple, dict]:
+            if type_.__name__ == id_:
+                return type_
+
+    elif isinstance(node, ast.Subscript):
+        base_type = _parse_type_node(node.value, names)
+        arg_type = _parse_type_node(node.slice, names)
+        return base_type[arg_type]
+
+    elif isinstance(node, ast.Tuple):
+        elts = node.elts
+        return tuple(_parse_type_node(elt, names) for elt in elts)
+
     raise ValueError(f"Code is not syntactically valid: {node}")
 
 

From dab44cd1fa5b18c8e46f595e889cebfa8ccaf461 Mon Sep 17 00:00:00 2001
From: Thomas D Ahle <thomas@ahle.dk>
Date: Sun, 3 Mar 2024 13:14:39 -0800
Subject: [PATCH 6/8] Python 3.9 compatability

---
 dspy/signatures/signature.py | 2 +-
 dspy/utils/dummies.py        | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/dspy/signatures/signature.py b/dspy/signatures/signature.py
index 6493a8ce19..8c1f161642 100644
--- a/dspy/signatures/signature.py
+++ b/dspy/signatures/signature.py
@@ -188,7 +188,7 @@ class MySignature(Signature):
     pass
 
 
-def ensure_signature(signature: str | Type[Signature]) -> Signature:
+def ensure_signature(signature: Union[str, Type[Signature]]) -> Signature:
     if signature is None:
         return None
     if isinstance(signature, str):
diff --git a/dspy/utils/dummies.py b/dspy/utils/dummies.py
index 3a37388073..1f6390536a 100644
--- a/dspy/utils/dummies.py
+++ b/dspy/utils/dummies.py
@@ -1,4 +1,5 @@
 import random
+from typing import Union
 from dsp.modules import LM
 import numpy as np
 from dsp.utils.utils import dotdict
@@ -8,7 +9,7 @@
 class DummyLM(LM):
     """Dummy language model for unit testing purposes."""
 
-    def __init__(self, answers: list[str] | dict[str, str], follow_examples: bool = False):
+    def __init__(self, answers: Union[list[str], dict[str, str]], follow_examples: bool = False):
         """Initializes the dummy language model.
 
         Parameters:

From fe321da85da1bc290a0bcd2e6c277d2d7e68a91c Mon Sep 17 00:00:00 2001
From: Thomas D Ahle <thomas@ahle.dk>
Date: Sun, 3 Mar 2024 13:28:51 -0800
Subject: [PATCH 7/8] Validate main signature fields

---
 dspy/functional/functional.py       | 48 ++++++++++++++++-------------
 tests/functional/test_functional.py | 17 ++++++++++
 2 files changed, 44 insertions(+), 21 deletions(-)

diff --git a/dspy/functional/functional.py b/dspy/functional/functional.py
index 041ee7abc5..aa82288295 100644
--- a/dspy/functional/functional.py
+++ b/dspy/functional/functional.py
@@ -155,31 +155,37 @@ def forward(self, **kwargs) -> dspy.Prediction:
             errors = {}
             parsed_results = defaultdict(list)
             # Parse the outputs
-            for name, field in signature.output_fields.items():
-                for i, completion in enumerate(result.completions):
-                    try:
+            for i, completion in enumerate(result.completions):
+                try:
+                    for name, field in signature.output_fields.items():
                         value = completion[name]
                         parser = field.json_schema_extra.get("parser", lambda x: x)
                         completion[name] = parser(value)
                         parsed_results[name].append(parser(value))
-                    except (pydantic.ValidationError, ValueError) as e:
-                        errors[name] = _format_error(e)
-                        # If we can, we add an example to the error message
-                        current_desc = field.json_schema_extra.get("desc", "")
-                        i = current_desc.find("JSON Schema: ")
-                        if i == -1:
-                            continue  # Only add examples to JSON objects
-                        suffix, current_desc = current_desc[i:], current_desc[:i]
-                        prefix = "You MUST use this format: "
-                        if (
-                            try_i + 1 < MAX_RETRIES
-                            and prefix not in current_desc
-                            and (example := self._make_example(field.annotation))
-                        ):
-                            signature = signature.with_updated_fields(
-                                name,
-                                desc=current_desc + "\n" + prefix + example + "\n" + suffix,
-                            )
+                    # Instantiate the actual signature with the parsed values.
+                    # This allow pydantic to validate the fields defined in the signature.
+                    _dummy = self.signature(
+                        **kwargs,
+                        **{key: value[i] for key, value in parsed_results.items()},
+                    )
+                except (pydantic.ValidationError, ValueError) as e:
+                    errors[name] = _format_error(e)
+                    # If we can, we add an example to the error message
+                    current_desc = field.json_schema_extra.get("desc", "")
+                    i = current_desc.find("JSON Schema: ")
+                    if i == -1:
+                        continue  # Only add examples to JSON objects
+                    suffix, current_desc = current_desc[i:], current_desc[:i]
+                    prefix = "You MUST use this format: "
+                    if (
+                        try_i + 1 < MAX_RETRIES
+                        and prefix not in current_desc
+                        and (example := self._make_example(field.annotation))
+                    ):
+                        signature = signature.with_updated_fields(
+                            name,
+                            desc=current_desc + "\n" + prefix + example + "\n" + suffix,
+                        )
             if errors:
                 # Add new fields for each error
                 for name, error in errors.items():
diff --git a/tests/functional/test_functional.py b/tests/functional/test_functional.py
index 029519bcfd..e012324f74 100644
--- a/tests/functional/test_functional.py
+++ b/tests/functional/test_functional.py
@@ -474,3 +474,20 @@ def test_parse_type_string():
 
     output = test(input=8, config=dict(n=3)).completions.output
     assert output == [0, 1, 2]
+
+
+def test_fields_on_base_signature():
+    class SimpleOutput(dspy.Signature):
+        output: float = dspy.OutputField(gt=0, lt=1)
+
+    lm = DummyLM(
+        [
+            "2.1",  # Bad output
+            "0.5",  # Good output
+        ]
+    )
+    dspy.settings.configure(lm=lm)
+
+    predictor = TypedPredictor(SimpleOutput)
+
+    assert predictor().output == 0.5

From 16be7a1bc84decdb417e2f0e4d337656db34b995 Mon Sep 17 00:00:00 2001
From: Thomas D Ahle <thomas@ahle.dk>
Date: Sun, 3 Mar 2024 14:12:52 -0800
Subject: [PATCH 8/8] Fixes to completions

---
 dspy/functional/functional.py       | 21 +++++++--------
 tests/functional/test_functional.py | 41 +++++++++++++++++++++++++++++
 tests/signatures/test_signature.py  |  2 ++
 3 files changed, 53 insertions(+), 11 deletions(-)

diff --git a/dspy/functional/functional.py b/dspy/functional/functional.py
index aa82288295..cb7b3669aa 100644
--- a/dspy/functional/functional.py
+++ b/dspy/functional/functional.py
@@ -10,7 +10,7 @@
 import json
 from dspy.primitives.prediction import Prediction
 
-from dspy.signatures.signature import ensure_signature
+from dspy.signatures.signature import ensure_signature, make_signature
 
 
 MAX_RETRIES = 3
@@ -83,7 +83,7 @@ def copy(self) -> "TypedPredictor":
     def _make_example(type_) -> str:
         # Note: DSPy will cache this call so we only pay the first time TypedPredictor is called.
         json_object = dspy.Predict(
-            dspy.Signature(
+            make_signature(
                 "json_schema -> json_object",
                 "Make a very succinct json object that validates with the following schema",
             ),
@@ -153,21 +153,20 @@ def forward(self, **kwargs) -> dspy.Prediction:
         for try_i in range(MAX_RETRIES):
             result = self.predictor(**modified_kwargs, new_signature=signature)
             errors = {}
-            parsed_results = defaultdict(list)
+            parsed_results = []
             # Parse the outputs
             for i, completion in enumerate(result.completions):
                 try:
+                    parsed = {}
                     for name, field in signature.output_fields.items():
                         value = completion[name]
                         parser = field.json_schema_extra.get("parser", lambda x: x)
                         completion[name] = parser(value)
-                        parsed_results[name].append(parser(value))
+                        parsed[name] = parser(value)
                     # Instantiate the actual signature with the parsed values.
                     # This allow pydantic to validate the fields defined in the signature.
-                    _dummy = self.signature(
-                        **kwargs,
-                        **{key: value[i] for key, value in parsed_results.items()},
-                    )
+                    _dummy = self.signature(**kwargs, **parsed)
+                    parsed_results.append(parsed)
                 except (pydantic.ValidationError, ValueError) as e:
                     errors[name] = _format_error(e)
                     # If we can, we add an example to the error message
@@ -199,9 +198,9 @@ def forward(self, **kwargs) -> dspy.Prediction:
                     )
             else:
                 # If there are no errors, we return the parsed results
-                # for name, value in parsed_results.items():
-                #    setattr(result, name, value)
-                return Prediction.from_completions(parsed_results)
+                return Prediction.from_completions(
+                    {key: [r[key] for r in parsed_results] for key in signature.output_fields}
+                )
         raise ValueError(
             "Too many retries trying to get the correct output format. " + "Try simplifying the requirements.",
             errors,
diff --git a/tests/functional/test_functional.py b/tests/functional/test_functional.py
index e012324f74..cabbc7cd09 100644
--- a/tests/functional/test_functional.py
+++ b/tests/functional/test_functional.py
@@ -11,6 +11,7 @@
 from dspy.functional import predictor, cot, FunctionalModule, TypedPredictor, functional
 from dspy.primitives.example import Example
 from dspy.teleprompt.bootstrap import BootstrapFewShot
+from dspy.teleprompt.vanilla import LabeledFewShot
 from dspy.utils.dummies import DummyLM
 
 
@@ -491,3 +492,43 @@ class SimpleOutput(dspy.Signature):
     predictor = TypedPredictor(SimpleOutput)
 
     assert predictor().output == 0.5
+
+
+def test_synthetic_data_gen():
+    class SyntheticFact(BaseModel):
+        fact: str = Field(..., description="a statement")
+        varacity: bool = Field(..., description="is the statement true or false")
+
+    class ExampleSignature(dspy.Signature):
+        """Generate an example of a synthetic fact."""
+
+        fact: SyntheticFact = dspy.OutputField()
+
+    lm = DummyLM(
+        [
+            '{"fact": "The sky is blue", "varacity": true}',
+            '{"fact": "The sky is green", "varacity": false}',
+            '{"fact": "The sky is red", "varacity": true}',
+            '{"fact": "The earth is flat", "varacity": false}',
+            '{"fact": "The earth is round", "varacity": true}',
+            '{"fact": "The earth is a cube", "varacity": false}',
+        ]
+    )
+    dspy.settings.configure(lm=lm)
+
+    generator = TypedPredictor(ExampleSignature)
+    examples = generator(config=dict(n=3))
+    for ex in examples.completions.fact:
+        assert isinstance(ex, SyntheticFact)
+    assert examples.completions.fact[0] == SyntheticFact(fact="The sky is blue", varacity=True)
+
+    # If you have examples and want more
+    existing_examples = [
+        dspy.Example(fact="The sky is blue", varacity=True),
+        dspy.Example(fact="The sky is green", varacity=False),
+    ]
+    trained = LabeledFewShot().compile(student=generator, trainset=existing_examples)
+
+    augmented_examples = trained(config=dict(n=3))
+    for ex in augmented_examples.completions.fact:
+        assert isinstance(ex, SyntheticFact)
diff --git a/tests/signatures/test_signature.py b/tests/signatures/test_signature.py
index 26fdfc7aa0..554d9b1274 100644
--- a/tests/signatures/test_signature.py
+++ b/tests/signatures/test_signature.py
@@ -82,6 +82,8 @@ def test_instructions_signature():
 def test_signature_instructions():
     sig1 = Signature("input1 -> output1", instructions="This is a test")
     assert sig1.instructions == "This is a test"
+    sig2 = Signature("input1 -> output1", "This is a test")
+    assert sig2.instructions == "This is a test"
 
 
 def test_signature_instructions_none():