code: def _except_if_failed(cls, event):
          
          if event.success is None:
              raise IOTSyncTimeout('Requested timed out', event)
          if not event.success:
              msg = "Request failed, unknown error"
              if isinstance(event.payload, Mapping):
                  if P_MESSAGE in event.payload:
                      msg = event.payload[P_MESSAGE]
                  try:
                      exc_class = cls.__exception_mapping[event.payload[P_CODE]]
                  except KeyError:
                      pass
                  else:
                      raise exc_class(msg, event)
  
              raise IOTException(msg, event)
docs: Raises an IOTException from the given event if it was not successful. Assumes timeout success flag on event
          has not been set yet.