def _nav_conf(lst, bp=None):
    """
    Shortcut for configuration navigation bars.

    Parameters
    ----------
    lst : list
        List of tuples like (Display name, route name, {url arguments}).
    bp : str, optional
        The name of blueprint that the routes passed belong to. If omitted, 
        a blueprint name must be passed with the route name.

    Returns
    -------
    list
        List of dictionaries with a caption and a (nested) url arguments dictionary.
    """
    output = []
    for caption, view, url_args in lst:
        if bp is not None:
            view = '.'.join([bp, view])
        url_args['endpoint'] = view
        d = {'caption': caption, 'url_args': url_args}
        output.append(d)
    return output