Chat client and server application in python

chat.py

import socket, sys, threading
PORT = 4444 
class ChatServer(threading.Thread):
    def __init__(self, port, host='192.168.1.3'):
        threading.Thread.__init__(self)
        self.port = port
        self.host = host
        self.server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.users = {} 
        try:
            self.server.bind((self.host, self.port))
        except socket.error:
            print('Bind failed %s' % (socket.error))
            sys.exit()
        self.server.listen(10)
    def exit(self):
        self.server.close()
    def run_thread(self, conn, addr):
        print('Client connected with ' + addr[0] + ':' + str(addr[1]))
        while True:
            data = conn.recv(1024)
            reply = b'OK...' + data
            print(reply)
            conn.sendall(reply) 
        conn.close() 
    def run(self):
        print('Waiting for connections on port %s' % (self.port))
        while True:
            conn, addr = self.server.accept()
            threading.Thread(target=self.run_thread, args=(conn, addr)).start()
class ChatClient(object):
    def __init__(self, port, host='192.168.1.3'):
        self.host = host
        self.port = port
        self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.socket.connect((self.host, port))
    def send_message(self, msg):
        pass
if __name__ == '__main__':
    server = ChatServer(PORT)
   
    server.run()