Makes use of Self Type in Contract factory methods

1. Uses the recently added `Self` Type for better type inference whenever Contract is subclassed

2. Fixes the return type of `Contract.factory` to indicate that a class is returned instead of an instance thereof

web3/contract/async_contract.py

@@ -9,6 +9,7 @@
     List,
     Optional,
     Sequence,
+    Type,
     cast,
 )
 
@@ -33,6 +34,9 @@
 from web3._utils.async_transactions import (
     fill_transaction_defaults as async_fill_transaction_defaults,
 )
+from web3._utils.compat import (
+    Self,
+)
 from web3._utils.contracts import (
     async_parse_block_identifier,
     parse_block_identifier_no_extra_call,
@@ -239,7 +243,7 @@ def __call__(self, *args: Any, **kwargs: Any) -> "AsyncContractFunction":
         return clone
 
     @classmethod
-    def factory(cls, class_name: str, **kwargs: Any) -> "AsyncContractFunction":
+    def factory(cls, class_name: str, **kwargs: Any) -> Self:
         return PropertyCheckingFactory(class_name, (cls,), kwargs)(kwargs.get("abi"))
 
     async def call(
@@ -449,7 +453,7 @@ def __init__(self, address: Optional[ChecksumAddress] = None) -> None:
     @classmethod
     def factory(
         cls, w3: "AsyncWeb3", class_name: Optional[str] = None, **kwargs: Any
-    ) -> "AsyncContract":
+    ) -> Type[Self]:
         kwargs["w3"] = w3
 
         normalizers = {
@@ -460,7 +464,7 @@ def factory(
         }
 
         contract = cast(
-            AsyncContract,
+            Type[Self],
             PropertyCheckingFactory(
                 class_name or cls.__name__,
                 (cls,),
@@ -491,7 +495,7 @@ def factory(
         return contract
 
     @classmethod
-    def constructor(cls, *args: Any, **kwargs: Any) -> "AsyncContractConstructor":
+    def constructor(cls, *args: Any, **kwargs: Any) -> Self:
         """
         :param args: The contract constructor arguments as positional arguments
         :param kwargs: The contract constructor arguments as keyword arguments
@@ -549,7 +553,7 @@ def __init__(
 
             self._functions = filter_by_type("function", self.abi)
             for func in self._functions:
-                fn: AsyncContractFunction = AsyncContractFunction.factory(
+                fn = AsyncContractFunction.factory(
                     func["name"],
                     w3=self.w3,
                     contract_abi=self.abi,

web3/contract/contract.py

@@ -8,6 +8,7 @@
     List,
     Optional,
     Sequence,
+    Type,
     cast,
 )
 
@@ -29,6 +30,9 @@
     filter_by_type,
     receive_func_abi_exists,
 )
+from web3._utils.compat import (
+    Self,
+)
 from web3._utils.contracts import (
     parse_block_identifier,
 )
@@ -235,7 +239,7 @@ def __call__(self, *args: Any, **kwargs: Any) -> "ContractFunction":
         return clone
 
     @classmethod
-    def factory(cls, class_name: str, **kwargs: Any) -> "ContractFunction":
+    def factory(cls, class_name: str, **kwargs: Any) -> Self:
         return PropertyCheckingFactory(class_name, (cls,), kwargs)(kwargs.get("abi"))
 
     def call(
@@ -448,7 +452,7 @@ def __init__(self, address: Optional[ChecksumAddress] = None) -> None:
     @classmethod
     def factory(
         cls, w3: "Web3", class_name: Optional[str] = None, **kwargs: Any
-    ) -> "Contract":
+    ) -> Type[Self]:
         kwargs["w3"] = w3
 
         normalizers = {
@@ -459,7 +463,7 @@ def factory(
         }
 
         contract = cast(
-            Contract,
+            Type[Self],
             PropertyCheckingFactory(
                 class_name or cls.__name__,
                 (cls,),
@@ -491,7 +495,7 @@ def factory(
         return contract
 
     @classmethod
-    def constructor(cls, *args: Any, **kwargs: Any) -> "ContractConstructor":
+    def constructor(cls, *args: Any, **kwargs: Any) -> Self:
         """
         :param args: The contract constructor arguments as positional arguments
         :param kwargs: The contract constructor arguments as keyword arguments
@@ -549,7 +553,7 @@ def __init__(
 
             self._functions = filter_by_type("function", self.abi)
             for func in self._functions:
-                fn: ContractFunction = ContractFunction.factory(
+                fn = ContractFunction.factory(
                     func["name"],
                     w3=self.w3,
                     contract_abi=self.abi,