server.py

import socket
sock = socket.socket()
sock.bind(('10.8.128.183',9991))
sock.listen(3)
A, addrA = sock.accept()
B, addrB = sock.accept()
A.send(b"x")
B.send(b"0")
#A.send(b"Hello!")
#B.send(b"Hello!")

cnt = -1
while True:
    cnt = (cnt + 1) % 2
    to = A#ходит B
    from_who = B
    if cnt == 0:#ходит A
        to = B
        from_who = A
        #x=0
    #to.send(b"Write smth")
    data = from_who.recv(1024)
    if not data:
        break
    elif data == b"end":
        A.send(b"end")
        break

    #print(b"from CLIENT ")
    #print(data)
    #print()
    #message = bytes(input(), 'utf-8')
    to.send(data)

#str = bytes(s, 'utf-8')
A.close()
B.colse()