def _apply_single_step(dist, params_event_ndims, slices, params_overrides):
  """"""
  if len(slices) == 1 and slices[0] == Ellipsis:
    # The path used by Distribution.copy: batch_slice(...args..., Ellipsis)
    override_dict = {}
  else:
    override_dict = _slice_params_to_dict(dist, params_event_ndims, slices)
  override_dict.update(params_overrides)
  parameters = dict(dist.parameters, **override_dict)
  new_dist = type(dist)(**parameters)
  return new_dist