code: def start(self):
          
          service_names = ', '.join(self.service_names)
          _log.info('starting services: %s', service_names)
  
          SpawningProxy(self.containers).start()
  
          _log.debug('services started: %s', service_names)
docs: Start all the registered services.
  
          A new container is created for each service using the container
          class provided in the __init__ method.
  
          All containers are started concurrently and the method will block
          until all have completed their startup routine.