nodes: 0, module; 1, function_definition; 2, function_name:is_sortable_index; 3, parameters; 4, block; 5, identifier:self; 6, identifier:index_name; 7, identifier:catalog; 8, expression_statement; 9, expression_statement; 10, if_statement; 11, return_statement; 12, comment:"""Returns whether the index is sortable
          """; 13, assignment; 14, not_operator; 15, block; 16, comparison_operator:index.meta_type in ["FieldIndex", "DateIndex"]; 17, identifier:index; 18, call; 19, identifier:index; 20, return_statement; 21, attribute; 22, list; 23, attribute; 24, argument_list; 25, False; 26, identifier:index; 27, identifier:meta_type; 28, string:"FieldIndex"; 29, string:"DateIndex"; 30, identifier:self; 31, identifier:get_index; 32, identifier:index_name; 33, identifier:catalog
code: def is_sortable_index(self, index_name, catalog):
          """Returns whether the index is sortable
          """
          index = self.get_index(index_name, catalog)
          if not index:
              return False
          return index.meta_type in ["FieldIndex", "DateIndex"]