user_pin and so_pin in Token.open() are documented as bytes, instead they are str

[sherpya]

In the docstring of the Token open function user_pin and so_pin are documented as bytes, but the code assumes they are strings:

      elif user_pin is not None:
            pin = user_pin.encode('utf-8')
            c_user_type = user_type if user_type is not None else CKU_USER
        elif so_pin is not None:
            pin = so_pin.encode('utf-8')
            c_user_type = CKU_SO

This causes pycharm (and other type checking tools) to complain