code: public function setFileName($fileName)
      {
          $fileName = preg_replace("([^\w\s\d\-_~,;\[\]\(\).])", '', $fileName);
          $fileName = preg_replace("([\.]{2,})", '', $fileName);
          $this->fileName = $fileName;
          return $this;
      }
docs: Set the Filename for response to be saved to
  @param $fileName
  @return self