<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def deletePlan(self, plan):
 """ Deletes a plan :param plan: Plan to delete :raises: FBchatException if request failed """

        data = {"event_reminder_id": plan.uid, "delete": "true", "acontext": ACONTEXT}
        j = self._post(self.req_url.PLAN_CHANGE, data, fix_request=True, as_json=True)