def test_order(self):
        assert (event.Priority.PRE_CORE
                > event.Priority.CORE
                > event.Priority.POST_CORE
                > event.Priority.PRE_DEFAULT
                > event.Priority.DEFAULT
                > event.Priority.POST_DEFAULT)
def _copy_vars(v_list):
  """Copy variables in v_list."""
  t_list = []
  for v in v_list:
    t_list.append(tf.identity(v))
  return t_list