How to use the pug-load.read function in pug-load

read: function (filename, loadOptions) {
      dependencies.push(filename);

      var contents;

      var replacementFunc = findReplacementFunc(plugins, 'read');
      if (replacementFunc) {
        contents = replacementFunc(filename, options);
      } else {
        contents = load.read(filename, loadOptions);
      }

      debug_sources[filename] = contents;
      return contents;
    }
  });