def get_function_class(function_name):
    """
    Return the type for the requested function

    :param function_name: the function to return
    :return: the type for that function (i.e., this is a class, not an instance)
    """

    if function_name in _known_functions:

        return _known_functions[function_name]

    else:

        raise UnknownFunction("Function %s is not known. Known functions are: %s" %
                              (function_name, ",".join(_known_functions.keys())))
Return the type for the requested function

    :param function_name: the function to return
    :return: the type for that function (i.e., this is a class, not an instance)