code: public function getAccessToken(): ApiAccessToken
      {
          if (!is_readable($this->filename)) {
              throw new UnableToAcquireAccessToken('Access Token is not found in the storage.');
          }
  
          $data = file_get_contents($this->filename);
  
          if (!empty($data) && substr_count($data, '|') === 1) {
              $data = explode('|', $data);
              return ApiAccessToken::create($data[0] ?? '', (int) ($data[1] ?? 0));
          }
  
          throw new UnableToAcquireAccessToken('Access Token is not found in the storage.');
      }
docs: {@inheritdoc}