message: Ensure wrong usages of run_v1_only are invalid
diff: @@ -1188,6 +1188,8 @@ def run_v1_only(reason, func=None):
  Returns:
  Returns a decorator that will conditionally skip the decorated test method.
  """
  + if not isinstance(reason, str):
  + raise ValueError("'reason' should be string, got {}".format(type(reason)))
  def decorator(f):
  if tf_inspect.isclass(f):
  