docs: def _copy_static_assets(self, output_dir):
          """Copy assets for the report to `output_dir`.
  
          :param output_dir: directory to output assets to
          :type output_dir: `str`
  
          """
          base_directory = 'assets/{}'.format(self._report_name)
          for asset in resource_listdir(self._package_name, base_directory):
              filename = resource_filename(
                  self._package_name, '{}/{}'.format(base_directory, asset))
              shutil.copy2(filename, output_dir)