def has_traits(cls, ignore=('config', 'parent')):
    """True if cls has any traits apart from the usual ones

    all our components have at least 'config' and 'parent' as traitlets
    this is inherited from `traitlets.config.Configurable` so we ignore them
    here.
    """
    return bool(set(cls.class_trait_names()) - set(ignore))
