<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def is_not_blocked(self, item: str) -> bool: """ Check if an item is _not_ already on the blacklist :param str item: The item to check :return: True, when the item is _not_ on the blacklist :rtype: bool """

        assert item is not None
        item = self._encode_item(item)
        connection = self.__get_connection()
        key = self.__redis_conf['blacklist_template'].format(item)
        value = connection.get(key)
        if value is None:
            BlackRed.__release_connection(connection)
            return True
        if self.__redis_conf['blacklist_refresh_ttl']:
            connection.expire(key, self.__redis_conf['blacklist_ttl'])
        BlackRed.__release_connection(connection)
        return False