Method _check_indexing_error

pandas/core/indexes/base.py:6090–6094

(self, key)

        return self._data.argsort(*args, **kwargs)

    def _check_indexing_error(self, key) -> None:
        if not is_scalar(key):
            # if key is not a scalar, directly raise an error (the code below
            # would convert to numpy arrays and raise later any way) - GH29926
            raise InvalidIndexError(key)

    @cache_readonly
    def _should_fallback_to_positional(self) -> bool: