Generics not supported

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Example:

from typen import enforce_type_hints

from typing import Generic, TypeVar

ModelT = TypeVar("ModelT")

class Test(Generic[ModelT]):
    def __init__(self, val:ModelT):
        self.val = val
    
    @enforce_type_hints
    def update(self, val:ModelT):
        self.val = val

    @enforce_type_hints
    def get(self) -> ModelT:
        return self.val

t=Test('foo')
t.update('bar') # Raises "ParameterTypeError: The 'val' parameter of 'update' must be ~ModelT, but a value of 'bar' <class 'str'> was specified."
t.get() # Raises "ReturnTypeError: The return type of 'get' must be ~ModelT, but a value of 'foo' <class 'str'> was returned."

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BTW: this is a cool library, thanks for putting it out there.

FYI: I'm playing around with using this just to do type-checking in my unit tests. I'm trying to make my unit tests fail if the method signature of mocked methods changes in incompatible ways. Ex:

from typen._enforcer import Enforcer
from unittest.mock import create_autospec
import ClassToMock, ClassToTest

def enforce_params(method, return_value=None):
  enforcer = Enforcer(method, ignore_self=True)
  def _side_effect(*args, **kwargs):
    args = (None,) + args # Add in dummy self value so args line up right
    enforcer.verify_args(args, kwargs)
    enforcer.verify_result(return_value)
    return return_value
  return _side_effect

def test_something():
  return_value = 'test string'
  mock = create_autospec(ClassToMock)
  mock.function_to_mock.side_effect = enforce_params(ClassToMock.function_to_mock, return_value)

  ClassToTest(mock).do_something()

  mock.function_to_mock.assert_called_once()

I'd like to turn this into a EnforcedMock class, although I'm going to need to put this aside for now and come back to it later. If I do, would that be something you're likely to accept a PR for?