<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def update(self):
 """Sync up changes to reminders. """

        params = {}
        return self.send(
            url=self._base_url + 'update',
            method='POST',
            json=params
        )