def send_tip(self, sender, receiver, message, context_uid, meta):
        """ Send a request to the ChangeTip API, to be delivered immediately. """
        assert self.channel is not None, "channel must be defined"

        # Add extra data to meta
        meta["mention_bot"] = self.mention_bot()

        data = json.dumps({
            "channel": self.channel,
            "sender": sender,
            "receiver": receiver,
            "message": message,
            "context_uid": context_uid,
            "meta": meta,
        })
        response = requests.post(self.get_api_url("/tips/"), data=data, headers={'content-type': 'application/json'})
        if response.headers.get("Content-Type", None) == "application/json":
            out = response.json()
            out["state"] = response.reason.lower()
            return out
        else:
            return {"state": response.reason.lower(), "error": "%s error submitting tip" % response.status_code}
Send a request to the ChangeTip API, to be delivered immediately.