fix: mypy type errors

arger/decorator.py

@@ -1,8 +1,9 @@
 from argparse import ArgumentParser
-from typing import Any, Callable, Dict, TypeVar, Optional
+from typing import Any, Callable, Dict, Optional, TypeVar
 
 from .parser import opterate
 
+
 CMD = "commands"
 F = TypeVar('F', bound=Callable[..., Any])
 
@@ -42,7 +43,7 @@ def install(code:int):
     def __init__(self, desc: Optional[str] = None, add_help=True):
         self.desc = desc
         self.add_help = add_help
-        self.funcs = {} # type: Dict[str, Any]
+        self.funcs = {}  # type: Dict[str, Any]
 
     @property
     def first_func(self):
@@ -64,12 +65,12 @@ def dispatch(self, *args):
             raise NotImplementedError("No function added.")
 
         parser = self.get_parser()
-        args = vars(parser.parse_args(args))
+        kwargs = vars(parser.parse_args(args))  # type: Dict[str, Any]
         if len(self.funcs) == 1:
-            return self.first_func(**args)
+            return self.first_func(**kwargs)
 
-        func = self.funcs[args[CMD]]
-        return func(**args)
+        func = self.funcs[kwargs[CMD]]
+        return func(**kwargs)
 
     def __call__(self, func: F) -> F:
         """Decorator.

tests/examples/arger_version.py

@@ -10,6 +10,8 @@
 arg = Arger("Test Commands")
 
 
+# pylint: disable=redefined-builtin
+# noinspection PyShadowingBuiltins
 @arg
 def list(dirname):
     """List contents

tests/test_wrapper.py

@@ -0,0 +1,26 @@
+import pytest
+from arger import Arger
+
+from .examples.doc_types import google_doc
+
+
+@pytest.fixture
+def arg():
+    return Arger("Test")
+
+
+def test_noargs(capsys, arg):
+    """Ensure a method that expects no arguments runs properly when it receives
+    none."""
+    arg(google_doc)  # equivalent of calling with decorator
+    with pytest.raises(SystemExit):
+        arg.dispatch()  # start function
+
+    capture = capsys.readouterr()
+    assert (
+        capture.err
+        == """\
+usage: pytest [-h] [-k KW1] [-w] param1 param2
+pytest: error: the following arguments are required: param1, param2
+"""
+    )