Method update

pymongo/common.py:1055–1061

(self, other: Mapping[str, Any])

            return default

    def update(self, other: Mapping[str, Any]) -> None:  # type: ignore[override]
        if isinstance(other, _CaseInsensitiveDictionary):
            for key in other:
                self[other.cased_key(key)] = other[key]
        else:
            for key in other:
                self[key] = other[key]

    def cased_key(self, key: str) -> Any:
        return self.__casedkeys[key.lower()]