def sort_group(self, field, order): """ Sorts Tuple elements within a group on the specified field in the specified Order. Note: Only groups of Tuple elements can be sorted. Groups can be sorted by multiple fields by chaining sort_group() calls. :param field:The Tuple field on which the group is sorted. :param order: The Order in which the specified Tuple field is sorted. See DataSet.Order. :return:A SortedGrouping with specified order of group element. """ child = OperationInfo() child_set = SortedGrouping(self._env, child, self._child_chain) child.identifier = _Identifier.SORT child.parent = self._info child.field = field child.order = order self._info.children.append(child) self._child_chain.append(child) self._env._sets.append(child) return child_set