def redact_event(self, room_id, event_id, reason=None, txn_id=None, timestamp=None):
        """Perform PUT /rooms/$room_id/redact/$event_id/$txn_id/

        Args:
            room_id(str): The room ID to redact the message event in.
            event_id(str): The event id to redact.
            reason (str): Optional. The reason the message was redacted.
            txn_id(int): Optional. The transaction ID to use.
            timestamp(int): Optional. Set origin_server_ts (For application services only)
        """
        if not txn_id:
            txn_id = self._make_txn_id()

        path = '/rooms/%s/redact/%s/%s' % (
            room_id, event_id, txn_id
        )
        content = {}
        if reason:
            content['reason'] = reason
        params = {}
        if timestamp:
            params["ts"] = timestamp
        return self._send("PUT", path, content, query_params=params)
Perform PUT /rooms/$room_id/redact/$event_id/$txn_id/

        Args:
            room_id(str): The room ID to redact the message event in.
            event_id(str): The event id to redact.
            reason (str): Optional. The reason the message was redacted.
            txn_id(int): Optional. The transaction ID to use.
            timestamp(int): Optional. Set origin_server_ts (For application services only)