def get_dir_from_zipfile(zip_file, fallback=None):
    """Return the name of the root folder in a zip file.

    :param zip_file: a :class:`zipfile.ZipFile` instance.
    :param fallback: if `None`, the name of the zip file is used. This is
        returned if the zip file contains more than one top-level directory,
        or none at all.
    """
    fallback = fallback or zip_file.filename
    directories = [name for name in zip_file.namelist() if name.endswith("/")
                   and len(PurePath(name).parts) == 1]
    return fallback if len(directories) > 1 else directories[0]
async def echo_server(loop, address, unix):
    if unix:
        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
    else:
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    sock.bind(address)
    sock.listen(5)
    sock.setblocking(False)
    if PRINT:
        print('Server listening at', address)
    with sock:
        while True:
            client, addr = await loop.sock_accept(sock)
            if PRINT:
                print('Connection from', addr)
            loop.create_task(echo_client(loop, client))