docs: function byExample() {
    var args = mlutil.asArray.apply(null, arguments);
    switch(args.length) {
    case 0:
      return {$query: []};
    case 1:
      var query = args[0];
      if (query.$query == null) {
        return {$query: query};
      }
      return query;
    default:
      return {$query: args};
    }
  }