code: def run(self, *, delay=None):
          
          for child in self.children:
              if isinstance(child, (group, pipeline)):
                  child.run(delay=delay)
              else:
                  self.broker.enqueue(child, delay=delay)
  
          return self
docs: Run the actors in this group.
  
          Parameters:
            delay(int): The minimum amount of time, in milliseconds,
              each message in the group should be delayed by.