Load state from cookie to the context

        :type context: satosa.context.Context
        :param context: Session context

def _load_state(self, context):
        """
        Load state from cookie to the context

        :type context: satosa.context.Context
        :param context: Session context
        """
        try:
            state = cookie_to_state(
                    context.cookie,
                    self.config["COOKIE_STATE_NAME"],
                    self.config["STATE_ENCRYPTION_KEY"])
        except SATOSAStateError as e:
            msg_tmpl = 'Failed to decrypt state {state} with {error}'
            msg = msg_tmpl.format(state=context.cookie, error=str(e))
            satosa_logging(logger, logging.WARNING, msg, None)
            state = State()
        finally:
            context.state = state