def test_add_already_added(self):
        prio_set_list = event._PrioritizedSetList()
        obj = object()
        prio_set_list.add(0, obj)

        with pytest.raises(ValueError) as excinfo:
            prio_set_list.add(0, obj)
        excinfo.match(r"has already been added")

        with pytest.raises(ValueError) as excinfo:
            prio_set_list.add(1, obj)
        excinfo.match(r"has already been added")
def from_mapping(
        self, mapping: t.Optional[t.Mapping[str, t.Any]] = None, **kwargs: t.Any
    ) -> bool:
        """Updates the config like :meth:`update` ignoring items with non-upper
        keys.

        .. versionadded:: 0.11
        """
        mappings: t.Dict[str, t.Any] = {}
        if mapping is not None:
            mappings.update(mapping)
        mappings.update(kwargs)
        for key, value in mappings.items():
            if key.isupper():
                self[key] = value
        return True