Method __setitem__

tornado/httputil.py:339–342

(self, name: str, value: str)

    # MutableMapping abstract method implementations.

    def __setitem__(self, name: str, value: str) -> None:
        norm_name = _normalize_header(name)
        self._combined_cache[norm_name] = value
        self._as_list[norm_name] = [value]

    def __contains__(self, name: object) -> bool:
        # This is an important optimization to avoid the expensive concatenation