def parse_block_mapping_key(self):
        if self.check_token(KeyToken):
            token = self.get_token()
            if not self.check_token(KeyToken, ValueToken, BlockEndToken):
                self.states.append(self.parse_block_mapping_value)
                return self.parse_block_node_or_indentless_sequence()
            else:
                self.state = self.parse_block_mapping_value
                return self.process_empty_scalar(token.end_mark)
        if not self.check_token(BlockEndToken):
            token = self.peek_token()
            raise ParserError("while parsing a block mapping", self.marks[-1],
                    token.id % "expected <block end>, but found %r", token.start_mark)
        token = self.get_token()
        event = MappingEndEvent(token.start_mark, token.end_mark)
        self.state = self.states.pop()
        self.marks.pop()
        return event
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/yaml-3.10/yaml/parser.py/Parser.parse_block_mapping_key/swapped operands of `%`