def __cache(self):
        """Generate an XHTML menu from collected information.

        This method is here to organize the construction process of a
        VerseLibrary instance. A menu is cached and bound to this name."""
        cache = '<select id="{0}" name="{0}">\n{1}'
        template = '        <option value="{}.{}">{}</option>\n'
        for gi, group in enumerate(self.__groups):
            cache += '    <optgroup label="{}">\n'.format(group.title)
            for fi, file in enumerate(group):
                cache += template.format(gi, fi, file.title)
            cache += '    </optgroup>\n'
        template = '    <option value="{}">{}</option>\n'
        for fi, file in enumerate(self.__option):
            cache += template.format(fi, file.title)
        return cache + '</select>'
Generate an XHTML menu from collected information.

        This method is here to organize the construction process of a
        VerseLibrary instance. A menu is cached and bound to this name.
recipes/Python/577049_Bible_Verse_Quiz__librarypy/recipe-577049.py