public function unmerge($phery_response)
    {
        if (is_string($phery_response)) {
            if (isset(self::$responses[$phery_response])) {
                unset($this->merged[self::$responses[$phery_response]->name]);
            }
        } elseif ($phery_response instanceof PheryResponse) {
            unset($this->merged[$phery_response->name]);
        } elseif ($phery_response === true) {
            $this->merged = array();
        }

        return $this;
    }