Multiuser Chatting using TCP Socket

Program :

Server Side :

import socket
import os
import threading
from threading import Thread

clients_lock = threading.Lock()
names = {}

def listener(client, address):
    '''Receive name'''	#Receive name of connected client
    names[client] = name		#Add name to names dictionary
    print (names[client]+" joined chat from IP:"+str(address[0])+" and Port:"+str(address[1]))
    with clients_lock:
        clients.add(client)		#Adding client socket value to clients list
        #print clients
    try:    
        while True:
            '''Receive data'''	#Receive data from client
            if not data:
                break
            else:
                data = names[client]+":"+str(data)	#Append data with client name
                #print data
                with clients_lock:
                    for c in clients:	#Send the data to all the clients
                        c.send(data)
    finally:
        with clients_lock:
            clients.remove(client)	#If client exit, then remove the client value
            client.close()

host = ''		#Server IP addres
port = 10015	#Port address 

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) #Creating a Socket
s.bind((host,port)) 	#Binding Port and IP address
s.listen(3) 		#Listen to connection
client, address = s.accept()
th = []		#Array for threads
print ("Server is listening for connections...")
while True:
	'''Accept Connection'''	#Accept a client connecion
	try:
	  #Launch a thread for each client request
	  th.append(Thread(target=listener, args = (client,address)).start())
	  
	except (KeyboardInterrupt, SystemExit):
	  cleanup_stop_thread();
	  s.close()		#Closing the socket
	  sys.exit()

Client Side:

#!/usr/bin/env python 

import socket 
from threading import Thread, Lock

def receiver(sock):
	while flag:
		data = sock.recv(size) 
		print ("\t\t"+data)

host = 'localhost' 		#Server IP addres
port = 10015			#Port address 
size = 1024 			#Size of packet data to receive
flag = True

'''Creating a Socket'''
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

'''Connect to Server'''
sock.bind((host,port))

# Start Receiver Thread
hop = Thread(target=receiver, args=(sock,))
hop.daemon = True
hop.start()	

data = bytes(input("Enter Message:"), encoding="UTF-8")		
sock.send(data) 
while data != 'quit':		#User will enter 'quit' to exit server
	data = bytes(input("Enter Message:"), encoding="UTF-8")		#Enter message to send to server
	sock.send(data) 			#Sending data to server

sock.close() 	#Closing the socket