Reload GTK theme on the fly.

def gtk():
    """Reload GTK theme on the fly."""
    # Here we call a Python 2 script to reload the GTK themes.
    # This is done because the Python 3 GTK/Gdk libraries don't
    # provide a way of doing this.
    if shutil.which("python2"):
        gtk_reload = os.path.join(MODULE_DIR, "scripts", "gtk_reload.py")
        util.disown(["python2", gtk_reload])

    else:
        logging.warning("GTK2 reload support requires Python 2.")