code: public function renderSystemIntent()
      {
          $out = [];
  
          $out['intent'] = 'actions.intent.DATETIME';
          $out['data'] = [
              '@type'      => 'type.googleapis.com/google.actions.v2.DateTimeValueSpec',
              'dialogSpec' => [
                  'requestDatetimeText' => $this->requestDateTimeText,
                  'requestDateText'     => $this->requestDateText,
                  'requestTimeText'     => $this->requestTimeText,
              ],
          ];
  
          return $out;
      }
docs: Render System Intent as array.
  
  @return null|array