def _remove_optional_none_type_hints(self, type_hints, defaults):
 # If argument has None as a default, typing.get_type_hints adds
 # optional None to the information it returns. We don't want that.
 for arg in defaults:
 if defaults[arg] is None and arg in type_hints:
 type_ = type_hints[arg]
 if self._is_union(type_):
 try:
 types = type_.__args__
 except AttributeError:
 # Python 3.5.2's typing uses __union_params__ instead
 # of __args__. This block can likely be safely removed
 # when Python 3.5 support is dropped
 types = type_.__union_params__
 if len(types) == 2 and types[1] is type(None):
 type_hints[arg] = types[0]