@classmethod
def _from_attr(cls, attr_name, attr_value):
    """
        Returns the enumeration item regarding to the attribute name and value,
        or None if not found

        :param attr_name: str: attribute's name
        :param attr_value: different values: key to search for
        :return: different types, label associated to the given key
        """
    return next(iter(filter(lambda x: getattr(x, attr_name) == attr_value,
        list(cls))), None)
