@classmethod
def count(cls, hash_key, range_key_condition=None, filter_condition=None,
    consistent_read=False, limit=None, rate_limit=None):
    """
        Count on an index
        """
    return cls.Meta.model.count(hash_key, range_key_condition=
        range_key_condition, filter_condition=filter_condition, index_name=
        cls.Meta.index_name, consistent_read=consistent_read, limit=limit,
        rate_limit=rate_limit)
