private function fire() {

      // fire request to shop
      $response = wp_remote_request( $this->url, $this->args );

      // validate raw response
      if( $this->validate_raw_response( $response ) === false ) {
        return false;
      }

      // decode the response
      $this->response = json_decode( wp_remote_retrieve_body( $response ) );

      // response should be an object
      if( ! is_object( $this->response ) ) {
        $this->error_message = 'No JSON object was returned.';
        return false;
      }

      return true;
    }