How to use the xcffib.ConnectionException function in xcffib

def configure(window):
    window.configure(
        width=100,
        height=100,
        x=0,
        y=0,
        border_width=1,
    )


for i in range(20):
    try:
        conn = xcffib.connect(display=sys.argv[1])
    except xcffib.ConnectionException:
        time.sleep(0.1)
        continue
    except Exception as v:
        print("Error opening test window: ", type(v), v, file=sys.stderr)
        sys.exit(1)
    break
else:
    print("Could not open window on display %s" % (sys.argv[1]), file=sys.stderr)
    sys.exit(1)

screen = conn.get_setup().roots[conn.pref_screen]

window = conn.generate_id()
background = conn.core.AllocColor(screen.default_colormap, 0x2828, 0x8383, 0xCECE).reply().pixel  # Color "#2883ce"
conn.core.CreateWindow(xcffib.CopyFromParent, window, screen.root,
                       100, 100, 100, 100, 1,

if verbose:
        xproc = subprocess.Popen(argv)
    else:
        with open(os.devnull, 'w') as devnull:
            xproc = subprocess.Popen(argv,
                                     stderr=subprocess.STDOUT, stdout=devnull)

    # Wait for the process to die, start accepting connections, or for
    # 5 seconds to pass
    # TODO: Refactor to be cleaner
    started = time.time()
    while xproc.poll() is None and (time.time() - started < 5):
        try:
            conn = xcffib.connect(display=':%d' % display_num,
                                  auth=b'MIT-MAGIC-COOKIE-1:' + magic_cookie)
        except xcffib.ConnectionException:
            time.sleep(0.1)  # Limit spinning when the server is slow to start
            continue
        else:
            if not xproc.poll():
                conn.disconnect()
                log.debug("X server on :%d accepting connections", display_num)
                return xproc

    if (time.time() - started) > 5:
        log.warning("Timed out while waiting for X server")
        if xproc.poll() is None:
            return xproc

    if xproc.returncode == 1 and os.path.exists(lock_path):
        log.debug("Race condition on display number %d", display_num)
        return None

def test_new_window(xdisplay):
    conn = xcbq.Connection(xdisplay)
    win = conn.create_window(1, 2, 640, 480)
    assert isinstance(win, xcbq.Window)
    geom = win.get_geometry()
    assert geom.x == 1
    assert geom.y == 2
    assert geom.width == 640
    assert geom.height == 480
    win.kill_client()
    with pytest.raises(xcffib.ConnectionException):
        win.get_geometry()

def _waitForXephyr(self):
        # Wait until Xephyr process dies
        while self.xephyr.poll() is None:
            try:
                conn = xcffib.connect(self.display)
                break
            except xcffib.ConnectionException:
                pass
            time.sleep(0.1)
        else:
            (stdout_data, stderr_data) = self.xephyr.communicate()
            raise AssertionError("Error launching Xephyr, quit with return code: {:d}\n"
                                 "stderr: {}\n"
                                 "stdout: {}".format(
                                     self.xephyr.returncode,
                                     stderr_data.decode(),
                                     stdout_data.decode()
                                 )
            )

        conn.disconnect()
        del conn

def x_reader(conn, callback):
    '''Try reading something from X connection to check if it's still alive.
    In case it isn't, call *callback*.
    '''
    try:
        conn.poll_for_event()
    except xcffib.ConnectionException:
        callback()