docs: function (args) {
              args = argsToArray(arguments);
              var order = [];
              args = compact(args).length ? args : null;
              if (args) {
                  args.forEach(function (a) {
                      if (isString(a)) {
                          order.push(this.stringToIdentifier(a));
                      } else if (a instanceof Identifier) {
                          order.push(a);
                      } else if (isFunction(a)) {
                          var res = a.apply(sql, [sql]);
                          order = order.concat(Array.isArray(res) ? res : [res]);
                      } else {
                          order.push(a);
                      }
                  }, this);
              } else {
                  order = null;
              }
              return this.mergeOptions({order: order});
          }