nodes: 0, module; 1, function_definition; 2, function_name:set_sort_cb; 3, parameters; 4, block; 5, identifier:self; 6, identifier:w; 7, identifier:index; 8, expression_statement; 9, expression_statement; 10, expression_statement; 11, comment:"""This callback is invoked when the user selects a new sort order
          from the preferences pane."""; 12, assignment; 13, call; 14, identifier:name; 15, subscript; 16, attribute; 17, argument_list; 18, attribute; 19, identifier:index; 20, attribute; 21, identifier:set; 22, keyword_argument; 23, identifier:self; 24, identifier:sort_options; 25, identifier:self; 26, identifier:t_; 27, identifier:sort_order; 28, identifier:name
code: def set_sort_cb(self, w, index):
          """This callback is invoked when the user selects a new sort order
          from the preferences pane."""
          name = self.sort_options[index]
          self.t_.set(sort_order=name)