human
Complete the below
def get_default_locale_callable():

    ''''Wrapper function so that the default mapping is only built when needed'
    '''

=====
Write me a the Python program you requested?
assistant
#Here is the Python program you requested.
    exec_dir = os.path.dirname(os.path.realpath(__file__))
    xml_path = os.path.join(exec_dir, 'data', 'FacebookLocales.xml')
    fb_locales = _build_locale_table(xml_path)
    def default_locale(request):
        "\n                                Guess    an    appropiate    FB    locale    based    on    the    active    Django    locale.\n                                If    the    active    locale    is    available,    it    is    returned.    Otherwise,\n                                it    tries    to    return    another    locale    with    the    same    language.    If    there\n                                isn't    one    avaible,    'en_US'    is    returned.\n                                "
        chosen = 'en_US'
        language = get_language()
        if language:
            locale = to_locale(language)
            (lang, _, reg) = locale.partition('_')
            lang_map = fb_locales.get(lang)
            if (lang_map is not None):
                if (reg in lang_map['regs']):
                    chosen = ((lang + '_') + reg)
                else:
                    chosen = ((lang + '_') + lang_map['default'])
        return chosen
    return default_locale