Method _get_argument

python/python3/tornado/web.py:530–542

(
        self,
        name: str,
        default: Union[None, str, _ArgDefaultMarker],
        source: Dict[str, List[bytes]],
        strip: bool = True,
    )

        return self._get_arguments(name, self.request.query_arguments, strip)

    def _get_argument(
        self,
        name: str,
        default: Union[None, str, _ArgDefaultMarker],
        source: Dict[str, List[bytes]],
        strip: bool = True,
    ) -> Optional[str]:
        args = self._get_arguments(name, source, strip=strip)
        if not args:
            if isinstance(default, _ArgDefaultMarker):
                raise MissingArgumentError(name)
            return default
        return args[-1]

    def _get_arguments(
        self, name: str, source: Dict[str, List[bytes]], strip: bool = True