## Single-expression echo server

(lambda s=__import__('socket'), i=__import__('itertools'):
    lambda port=9000, r=s.socket(s.AF_INET, s.SOCK_STREAM):
        all(r.setsockopt(s.SOL_SOCKET, s.SO_REUSEADDR, 1),
            r.bind(('', port)),
            r.listen(5),
            set(map(lambda c:
                c[0].sendall(c[0].recv(1024)) and
                c[0].close(),
                (r.accept() for _ in i.count(1))))))()()