code: def download_file(self, fname, output_dir):
      
      if fname not in self.competition_files:  # pylint: disable=unsupported-membership-test
        raise ValueError("%s is not one of the competition's "
                         "files: %s" % (fname, self.competition_files))
      command = [
          "kaggle",
          "competitions",
          "download",
          "--file",
          fname,
          "--path",
          output_dir,
          "-c",
          self._competition_name,
      ]
      _run_kaggle_command(command, self._competition_name)
      return os.path.join(output_dir, fname)
docs: Downloads competition file to output_dir.