def media_urls(request):
    media_urls = URLCycle(url_list=settings.MEDIA_URLS)
    return {'MEDIA_URL':media_urls}
    
class URLCycle(object):
    def __init__(self,url_list):
        self.urls = url_list
        self.iter = 0
        
    def __str__(self):
        if self.iter == len(self.urls):
            self.iter = 0
        url = self.urls[self.iter]
        self.iter += 1
        return url