@classmethod
def filter(cls, o):
    """
            Filter object with this class in data
            return
            True when object contains this datablock
            False otherwhise
            usage:
            class_name.filter(object) from outside world
            self.__class__.filter(object) from instance
        """
    try:
        return cls.__name__ in o.data
    except:
        pass
    return False
