code: def remaining(self):
          
          if self._expired:
              raise Expired()
  
          obj = {
              u'ID': self.lease_id,
          }
          data = json.dumps(obj).encode('utf8')
  
          url = u'{}/v3alpha/kv/lease/timetolive'.format(self._client._url).encode()
          response = yield treq.post(url, data, headers=self._client._REQ_HEADERS)
  
          obj = yield treq.json_content(response)
  
          ttl = obj.get(u'TTL', None)
          if not ttl:
              self._expired = True
              raise Expired()
  
          # grantedTTL = int(obj[u'grantedTTL'])
          # header = Header._parse(obj[u'header']) if u'header' in obj else None
  
          returnValue(ttl)
docs: Get the remaining time-to-live of this lease.
  
          :returns: TTL in seconds.
          :rtype: int