code: def last(self, limit=1, **kwargs):
          return self.collection_instance(
              self.db_adapter(
                  db_name=kwargs.get('db'),
                  role=kwargs.get('role', 'replica')
                  ).select(
                      where='created_at IS NOT NULL',
                      order='created_at DESC',
                      limit=limit
                      )
                  )