A multithreaded chat server

So let's put this to use and write our chat server. Make a new file called 2.1-chat_server-multithread.py and put the following code in it:

import threading, queue
import tincanchat

HOST = tincanchat.HOST
PORT = tincanchat.PORT

send_queues = {}
lock = threading.Lock()

def handle_client_recv(sock, addr):
    """ Receive messages from client and broadcast them to
        other clients until client disconnects """
    rest = bytes()
    while True:
        try:
            (msgs, rest) = tincanchat.recv_msgs(sock, rest)
        except (EOFError, ConnectionError):
            handle_disconnect(sock, addr)
            break
        for msg in msgs:
            msg = '{}: {}'.format(addr, msg)
            print(msg)
            broadcast_msg(msg)

def handle_client_send(sock, q, addr):
    """ Monitor queue for new messages, send them to client as
        they arrive """
    while True:
        msg = q.get()
        if msg == None: break
        try:
            tincanchat...