code: def get_all(self, cat):
          
          return self._get_from_local_cache(cat) or self._get_from_cache(cat) or self._get_from_db(cat)
docs: if data can't found in cache then it will be fetched from db,
           parsed and stored to cache for each lang_code.
  
          :param cat: cat of catalog data
          :return: