docs: async def stop_slaves(self, timeout=1):
          """Stop all the slaves by sending a stop-message to their managers.
  
          :param int timeout:
              Timeout for connecting to each manager. If a connection can not
              be made before the timeout expires, the resulting error for that
              particular manager is logged, but the stopping of other managers
              is not halted.
          """
          for addr in self.addrs:
              try:
                  r_manager = await self.env.connect(addr, timeout=timeout)
                  await r_manager.stop()
              except:
                  self._log(logging.WARNING, "Could not stop {}".format(addr))