code: async def Check(self, stream):
          
          request = await stream.recv_message()
          checks = self._checks.get(request.service)
          if checks is None:
              await stream.send_trailing_metadata(status=Status.NOT_FOUND)
          elif len(checks) == 0:
              await stream.send_message(HealthCheckResponse(
                  status=HealthCheckResponse.SERVING,
              ))
          else:
              for check in checks:
                  await check.__check__()
              await stream.send_message(HealthCheckResponse(
                  status=_status(checks),
              ))
docs: Implements synchronous periodic checks