code: public function actionFlushAll()
      {
          $caches = $this->findCaches();
          $cachesInfo = [];
  
          if (empty($caches)) {
              $this->notifyNoCachesFound();
              return ExitCode::OK;
          }
  
          foreach ($caches as $name => $class) {
              $cachesInfo[] = [
                  'name' => $name,
                  'class' => $class,
                  'is_flushed' => $this->canBeFlushed($class) ? Yii::$app->get($name)->flush() : false,
              ];
          }
  
          $this->notifyFlushed($cachesInfo);
      }
docs: Flushes all caches registered in the system.