code: def _memoize(self, name, getter, *args, **kwargs):
          
          field = "custom_m_" + name
          cached = self.fetch(field)
          if cached:
              value = cached
          else:
              value = getter(*args, **kwargs)
              self._make_it_so("caching %s=%r for" % (name, value,), ["custom.set"], field[7:], value)
              self._fields[field] = value
          return value
docs: Cache a stable expensive-to-get item value for later (optimized) retrieval.