code: def on_join(self, connection, event):
          
          #from time import sleep; sleep(10)  # Simulate a slow connection
          nickname = self.get_nickname(event)
          nickname_color = color(nickname)
          self.nicknames[nickname] = nickname_color
          self.namespace.emit("join")
          self.namespace.emit("message", nickname, "joins", nickname_color)
          self.emit_nicknames()
docs: Someone joined the channel - send the nicknames list to the
          WebSocket.