code: def declare_actor(self, actor):  # pragma: no cover
          
          self.emit_before("declare_actor", actor)
          self.declare_queue(actor.queue_name)
          self.actors[actor.actor_name] = actor
          self.emit_after("declare_actor", actor)
docs: Declare a new actor on this broker.  Declaring an Actor
          twice replaces the first actor with the second by name.
  
          Parameters:
            actor(Actor): The actor being declared.