code: def refresh(self, fields=None, **kwargs):
          
          cond = self.c[self._primary_field]==self._key
          query = self.filter(cond, **kwargs)
          if not fields:
              fields = list(self.table.c)
          
          v = query.values_one(*fields)
          if not v:
              raise NotFound('Instance <{0}:{1}> can not be found'.format(self.tablename, self._key))
          
          d = self._data_prepare(v.items())
          self.update(**d)
          self.set_saved()
docs: Re get the instance of current id