code: public function redirect($url, $statusCode = 302)
      {
          return Yii::$app->getResponse()->redirect(Url::to($url), $statusCode);
      }
docs: Redirects the browser to the specified URL.
  This method is a shortcut to [[Response::redirect()]].
  
  You can use it in an action by returning the [[Response]] directly:
  
  ```php
  // stop executing this action and redirect to login page
  return $this->redirect(['login']);
  ```
  
  @param string|array $url the URL to be redirected to. This can be in one of the following formats:
  
  - a string representing a URL (e.g. "http://example.com")
  - a string representing a URL alias (e.g. "@example.com")
  - an array in the format of `[$route, ...name-value pairs...]` (e.g. `['site/index', 'ref' => 1]`)
  [[Url::to()]] will be used to convert the array into a URL.
  
  Any relative URL will be converted into an absolute one by prepending it with the host info
  of the current request.
  
  @param integer $statusCode the HTTP status code. Defaults to 302.
  See <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html>
  for details about HTTP status code
  @return Response the current response object