import socket
from contextlib import closing


def find_free_port():
    with closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as s:
        try:
            s.bind(('', 0))
            s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        except Exception:
            return None
        else:
            return s.getsockname()[1]