def delete_cookie(
        self,
        key: str,
        *,
        domain: str = "localhost",
        path: str = "/",
    ) -> None:
        """Delete a cookie if it exists. Cookies are uniquely identified by
        ``(domain, path, key)``.

        :param key: The decoded form of the key for the cookie.
        :param domain: The domain the cookie was set for.
        :param path: The path the cookie was set for.

        .. versionchanged:: 3.0
            The ``server_name`` parameter is removed. The first parameter is
            ``key``. Use the ``domain`` parameter instead.

        .. versionchanged:: 3.0
            The ``secure``, ``httponly`` and ``samesite`` parameters are removed.

        .. versionchanged:: 2.3
            The ``domain`` parameter defaults to ``localhost``.
        """
        if self._cookies is None:
            raise TypeError(
                "Cookies are disabled. Create a client with 'use_cookies=True'."
            )

        self._cookies.pop((domain, path, key), None)
Delete a cookie if it exists. Cookies are uniquely identified by
        ``(domain, path, key)``.

        :param key: The decoded form of the key for the cookie.
        :param domain: The domain the cookie was set for.
        :param path: The path the cookie was set for.

        .. versionchanged:: 3.0
            The ``server_name`` parameter is removed. The first parameter is
            ``key``. Use the ``domain`` parameter instead.

        .. versionchanged:: 3.0
            The ``secure``, ``httponly`` and ``samesite`` parameters are removed.

        .. versionchanged:: 2.3
            The ``domain`` parameter defaults to ``localhost``.
        
src/werkzeug/test.py