def METHOD_NAME(self) -> Optional[str]:
    """
    Returns the description of the command-line tool that is shown when invoked with --help.
    By default, the description is taken from the tool class, or from the module containing
    the tool's class, in that order of preference.
    """
    class_docstring = self.__class__.__doc__
    if class_docstring is not None and class_docstring.strip():
        return class_docstring
    return sys.modules[self.__class__.__module__].__doc__