human
Can you provide a the Python program you requested given the following:
Complete the below
def format_navigation_links(additional_languages, default_lang, messages, strip_indexes=False):

    ''''Return the string to configure NAVIGATION_LINKS.'
    '''
assistant
#Here is the Python program you requested.
    f = u'                {0}:    (\n                                ("{1}/archive.html",    "{2[Archive]}"),\n                                ("{1}/categories/{3}",    "{2[Tags]}"),\n                                ("{1}/rss.xml",    "{2[RSS    feed]}"),\n                ),'
    pairs = []
    def get_msg(lang):
        'Generate    a    smaller    messages    dict    with    fallback.'
        fmsg = {}
        for i in (u'Archive', u'Tags', u'RSS    feed'):
            if messages[lang][i]:
                fmsg[i] = messages[lang][i]
            else:
                fmsg[i] = i
        return fmsg
    if strip_indexes:
        index_html = ''
    else:
        index_html = 'index.html'
    pairs.append(f.format('DEFAULT_LANG', '', get_msg(default_lang), index_html))
    for l in additional_languages:
        pairs.append(f.format(json.dumps(l, ensure_ascii=False), ('/' + l), get_msg(l), index_html))
    return u'{{\n{0}\n}}'.format('\n\n'.join(pairs))