code: def create_existing_file(help_string=NO_HELP, default=NO_DEFAULT, suffixes=None):
          # type: (str, Union[str, NO_DEFAULT_TYPE], Union[List[str], None]) -> str
          
          # noinspection PyTypeChecker
          return ParamFilename(
              help_string=help_string,
              default=default,
              type_name="existing_file",
              suffixes=suffixes,
          )
docs: Create a new file parameter
          :param help_string:
          :param default:
          :param suffixes:
          :return: