<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def cancel(self):
 """Cancel the current transfer. :rtype: ``bool`` """


        method, url = get_URL('cancel')

        payload = {
            'apikey': self.config.get('apikey'),
            'transferid': self.transfer_id,
            'transferkey': self.transfer_info.get('transferkey')
            }

        res = getattr(self.session, method)(url, params=payload)

        if res.status_code == 200:
            self._complete = True
            return True

        hellraiser(res)