def punsubscribe(pattern)
      @psub_callbacks.delete(pattern)
      @psubs.delete(pattern)
      raw_send_command(:punsubscribe, [pattern])
      return pubsub_deferrable(pattern)
    end
def punsubscribe(pattern)
      @psub_callbacks.delete(pattern)
      @psubs.delete(pattern)
      raw_send_command(:punsubscribe, [pattern])
      return pubsub_deferrable(pattern)
    end
Pattern unsubscribe all callbacks for a given pattern

 @return [Deferrable] Redis punsubscribe call