import socket
from select import select
tasks = []
to_read = {}
to_write = {}
def server():
    serv_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    serv_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    serv_socket.bind(('localhost', 5000))
    serv_socket.listen()
    while True:
        yield ('read', serv_socket)
        client_socket, addr = serv_socket.accept()
        tasks.append(client(client_socket))
def client(client_socket):
    while True:
        yield ('read', client_socket)
        request = client_socket.recv(4096)
        if not request:
            break
        else:
            yield ('write', client_socket)
            client_socket.send('Request from the serv_socket..\n'.encode())
    client_socket.close()
def event_loop():
    while any([tasks, to_read, to_write]):
        while not tasks:
            ready_to_read, ready_to_write, _ = select(to_read, to_write, [])
            for sock in ready_to_read:
                tasks.append(to_read.pop(sock))
            for sock in ready_to_write:
                tasks.append(to_write.pop(sock))
        try:
            task = tasks.pop(0)
            reason, sock = next(task)
            if reason == 'read':
                to_read[sock] = task
            if reason == 'write':
                to_write[sock] = task
        except StopIteration:
            pass
tasks.append(server())
event_loop()

 def do_iter():
    i = 50
    while i > 0:
        a = 1
        b = a-i
        i += -1
        yield b

 obj_iter = do_iter()
next(obj_iter)

 obj_iter = do_iter()