def parse_flow_mapping_key(self, first=False):
        if not self.check_token(FlowMappingEndToken):
            if not first:
                if self.check_token(FlowEntryToken):
                    self.get_token()
                else:
                    token = self.peek_token()
                    raise ParserError("while parsing a flow mapping", self.marks[-1],
                            token.id % "expected ',' or '}', but got %r", token.start_mark)
            if self.check_token(KeyToken):
                token = self.get_token()
                if not self.check_token(ValueToken,
                        FlowEntryToken, FlowMappingEndToken):
                    self.states.append(self.parse_flow_mapping_value)
                    return self.parse_flow_node()
                else:
                    self.state = self.parse_flow_mapping_value
                    return self.process_empty_scalar(token.end_mark)
            elif not self.check_token(FlowMappingEndToken):
                self.states.append(self.parse_flow_mapping_empty_value)
                return self.parse_flow_node()
        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_flow_mapping_key/swapped operands of `%`