code: def _updater_wrapper(updater):
      
      def updater_handle(key, lhs_handle, rhs_handle, _):
          """ ctypes function """
          lhs = _ndarray_cls(NDArrayHandle(lhs_handle))
          rhs = _ndarray_cls(NDArrayHandle(rhs_handle))
          updater(key, lhs, rhs)
      return updater_handle
docs: A wrapper for the user-defined handle.