code: def to_json(self, filename=None,
                  encoding="utf-8", errors="strict", **json_kwargs):
          
          return _to_json(self.to_dict(), filename=filename,
                          encoding=encoding, errors=errors, **json_kwargs)
docs: Transform the Box object into a JSON string.
  
          :param filename: If provided will save to file
          :param encoding: File encoding
          :param errors: How to handle encoding errors
          :param json_kwargs: additional arguments to pass to json.dump(s)
          :return: string of JSON or return of `json.dump`