@classmethod
def hget(cls, key, hash_key):
    """Get the value for a hash key in the hash table at the specified key.

        :param string key: The key to fetch.
        :param string hash_key: The hash key to fetch value for in the hash
            table.
        :returns string: The value corresponding to the hash key in the hash
            table. If either ``key`` or ``hash_key`` is not found, ``None`` is
            returned.
        :raises redis.ResponseError: If ``key`` holds something other than a
            hash table.
        """
    return cls._instance.hget(key, hash_key)
