code: def start (self):
          '''
          Starts (Subscribes) the client.
  
          '''
          self.subrgb = rospy.Subscriber(self.topicrgb, ImageROS)
          self.subd = rospy.Subscriber(self.topicd, ImageROS)
          self.ts = message_filters.ApproximateTimeSynchronizer([subrgb, subd], 1, 0.1, allow_headerless=True)
          self.ts.registerCallback(self.__callbackf start (self):
          '''
          Starts (Subscribes) the client.
  
          '''
          self.subrgb = rospy.Subscriber(self.topicrgb, ImageROS)
          self.subd = rospy.Subscriber(self.topicd, ImageROS)
          self.ts = message_filters.ApproximateTimeSynchronizer([subrgb, subd], 1, 0.1, allow_headerless=True)
          self.ts.registerCallback(self.__callback)
docs: Starts (Subscribes) the client.