def define_relevant_expr(obj_name, obj_slugs=None, obj_ids=None):
  """Returns relevant op expression"""
  obj = {
      "op": {"name": "relevant"},
      "object_name": obj_name,
  }
  if obj_slugs:
    obj["slugs"] = obj_slugs
  if obj_ids:
    obj["ids"] = obj_ids
  return obj