code: def delete_ptr_records(self, device, ip_address=None):
          
          device_type = self._resolve_device_type(device)
          href, svc_name = self._get_ptr_details(device, device_type)
          uri = "/rdns/%s?href=%s" % (svc_name, href)
          if ip_address:
              uri = "%s&ip=%s" % (uri, ip_address)
          resp, resp_body = self._async_call(uri, method="DELETE",
                  has_response=False,
                  error_class=exc.PTRRecordDeletionFailed)
          return resp_body.get("status") == "COMPLETED"
docs: Deletes the PTR records for the specified device. If 'ip_address' is
          supplied, only the PTR records with that IP address will be deleted.