Expand(flatten) url patterns

def expand_patterns(urlpatterns):
    new_patterns = []
    def recursive_expand(patterns):
        for p in patterns:
            if getattr(p,'url_patterns',False):
                recursive_expand(p.url_patterns)
            else:
                new_patterns.append(p)
    recursive_expand(patterns)
    return new_patterns

# Example usage, a Sitemap class
class StaticSitemap(Sitemap):
    """Return the static sitemap items"""
    priority = 0.4
    changefreq = 'yearly'

    def __init__(self, patterns):
        self.patterns = expand_patterns(patterns)
        self._items = {}
        self._initialize()

    def _initialize(self):
        do_not_show = ['logout','admin','login']
        for p in self.patterns:
            if [url for url in do_not_show if url in p.regex.pattern]:
                # do not show urls with this word in them
                continue
            if p.regex.groups:
                # do not show dynamic urls, we handle those in another Sitemap class
                continue
            if 'template_name' in p.default_args or 'template' in p.default_args :
                # only urls with templates, because we get mtime from the file
               if getattr(p,'name',False):
                   # only views with names so reverse() can work on them
                   self._items[p.name] = self._get_modification_date(p)

    def _get_modification_date(self, p):
        # We get the modification date from the template itself
        if getattr(p,'default_args',None):
            if 'template_name' in p.default_args:
                template = p.default_args['template_name']
            elif 'template' in p.default_args:
                template = p.default_args['template']
            template_path = self._get_template_path(template)
            mtime = os.stat(template_path).st_mtime
            return datetime.datetime.fromtimestamp(mtime)

    def _get_template_path(self, template_path):
        for template_dir in settings.TEMPLATE_DIRS:
            path = os.path.join(template_dir, template_path)
            if os.path.exists(path):
                return path
        return None

    def items(self):
        return self._items.keys()

    def changefreq(self, obj):
        return 'monthly' #Todo unhardcode this, somehow

    def lastmod(self, obj):
        return self._items[obj]

    def location(self, obj):
        return urlresolvers.reverse(obj)