nodes: 0, module; 1, function_definition; 2, function_name:sort_by_efficiency; 3, parameters; 4, block; 5, identifier:self; 6, default_parameter; 7, expression_statement; 8, expression_statement; 9, return_statement; 10, identifier:reverse; 11, True; 12, comment:"""Sort the configurations in place. items with highest efficiency come first"""; 13, call; 14, identifier:self; 15, attribute; 16, argument_list; 17, attribute; 18, identifier:sort; 19, keyword_argument; 20, keyword_argument; 21, identifier:self; 22, identifier:_confs; 23, identifier:key; 24, lambda; 25, identifier:reverse; 26, identifier:reverse; 27, lambda_parameters; 28, attribute; 29, identifier:c; 30, identifier:c; 31, identifier:efficiency
code: def sort_by_efficiency(self, reverse=True):
          """Sort the configurations in place. items with highest efficiency come first"""
          self._confs.sort(key=lambda c: c.efficiency, reverse=reverse)
          return self