The following patch corrects the docstring of `inspect.Parameter`, as the `default` and `annotation` attributes are in fact set to `empty` if no value is provided, and the `kind` attribute is in fact an `int` (more precisely, a `_ParameterKind`).  It also reimplements the `_ParameterKind` type as an `IntEnum`, as the previous implementation (which predates stdlib enums) was more or less a hand-rolled `IntEnum`.