/**
  * Constructor.
  *
  * @param UserCheckerInterface $userChecker An UserCheckerInterface interface
  * @param string               $key         A key
  * @param string               $providerKey A provider key
  */
 public function __construct(UserCheckerInterface $userChecker, $key, $providerKey)
 {
     parent::__construct($userChecker, $key, $providerKey);
     $this->providerKey = $providerKey;
 }