code: private function generateExecuteFragment() {
          $body = '';
  
          if ($this->operationDefinition->getNeedsSigning()) {
              $body .= '$request = $this->api->signRequest($request);'.PHP_EOL;
          }
  
          $body .= '$response = $this->api->execute($request, $this);'.PHP_EOL;
          $body .= '$this->response = $response;'.PHP_EOL;
  
          return $body; 
      }
docs: Helper method to avoid repitition
  @return string