code: def _get_last_worker_died(self):
          
          for service_id in list(self._running_services.keys()):
              # We copy the list to clean the orignal one
              processes = list(self._running_services[service_id].items())
              for process, worker_id in processes:
                  if not process.is_alive():
                      self._run_hooks('dead_worker', service_id, worker_id,
                                      process.exitcode)
                      if process.exitcode < 0:
                          sig = _utils.signal_to_name(process.exitcode)
                          LOG.info('Child %(pid)d killed by signal %(sig)s',
                                   dict(pid=process.pid, sig=sig))
                      else:
                          LOG.info('Child %(pid)d exited with status %(code)d',
                                   dict(pid=process.pid, code=process.exitcode))
                      del self._running_services[service_id][process]
                      return service_id, worker_id
docs: Return the last died worker information or None