code: def get(self, name: str, sig: Tuple) -> Optional[object]:
          
          if name not in self._cache:
              return None
          if self._cache[name].sig != sig:
              del self._cache[name]
              self._update()
              return None
          with open(self._cache[name].loc, 'rb') as f:
              return pickle.load(f)
docs: Return the object representing name if it is cached
          :param name: name of object
          :param sig: unique signature of object
          :return: object if exists and signature matches