code: public function getToken($forceRefresh = false)
      {
          $cached = $this->authorizer->getAccessToken();
  
          if ($forceRefresh || empty($cached)) {
              return $this->renewAccessToken();
          }
  
          return $cached;
      }
docs: Get token from WeChat API.
  
  @param bool $forceRefresh
  
  @return string