text: import rospy
  from std_msgs.msg import String
  from flask_socketio import SocketIO
  
  from .subscriber import ServerSub
  
  class ChatSub(ServerSub):
      """
      Subscriber to receive chat messages
      """
      def __init__(self, topic, sio_route, sio):
          super().__init__(topic, String)
          self.sio_route = sio_route
          self.sio = sio
  
      def callback(self, msg):
          packet = {
              'text': msg.data
          }
          self.sio.emit(self.sio_route, packet, broadcast=True)