code: def theme_lookup(self):
          
  
          # check cache
          cache_key = 'theme:%s' % self.domain_unsplit
          theme = cache.get(cache_key)
          if theme:
              THEME.value = theme
              return None
  
          # check database
          if hasattr(self.site, 'themes'):
              try:
                  themes = [theme.name for theme in self.site.themes.all()]
                  THEME.value = themes[0]
                  cache.set(cache_key, THEME.value, 5*60)
              except:
                  return False
          return None
docs: Returns theme based on site
  
          Returns None and sets settings.THEME if able to find a theme object by site.
  
          Otherwise, returns False.