def _validate_game_object(self, op="<STR_LIT>"):
if self._g is None:<EOL><INDENT>raise ValueError(<EOL>"<STR_LIT>"<EOL>"<STR_LIT>"<EOL>)<EOL><DEDENT>if not isinstance(self._g, GameObject):<EOL><INDENT>raise TypeError(<EOL>"<STR_LIT>".format(op)<EOL>)<EOL><DEDENT>
A helper method to provide validation of the game object (_g). If the
game object does not exist or if (for any reason) the object is not a GameObject,
then an exception will be raised.

:param op: A string describing the operation (e.g. guess, save, etc.) taking place
:return: Nothing