def delenv(self, name: str, raising: bool = True) -> None:
        """Delete ``name`` from the environment.

        Raises ``KeyError`` if it does not exist, unless ``raising`` is set to
        False.
        """
        environ: MutableMapping[str, str] = os.environ
        self.delitem(environ, name, raising=raising)
Delete ``name`` from the environment.

        Raises ``KeyError`` if it does not exist, unless ``raising`` is set to
        False.
        
src/_pytest/monkeypatch.py