def delete_cookie(self, key, path='/', domain=None):
        """Delete a cookie.  Fails silently if key doesn't exist.

        :param key: the key (name) of the cookie to be deleted.
        :param path: if the cookie that should be deleted was limited to a
                     path, the path has to be defined here.
        :param domain: if the cookie that should be deleted was limited to a
                       domain, that domain has to be defined here.
        """
        self.set_cookie(key, expires=0, max_age=0, path=path, domain=domain)
Delete a cookie.  Fails silently if key doesn't exist.

        :param key: the key (name) of the cookie to be deleted.
        :param path: if the cookie that should be deleted was limited to a
                     path, the path has to be defined here.
        :param domain: if the cookie that should be deleted was limited to a
                       domain, that domain has to be defined here.