def test_deprecated_missing_args(self):
    date = "2016-07-04"
    instructions = "This is how you update..."

    def _fn(arg0, arg1, deprecated=None):
      return arg0 + arg1 if deprecated else arg1 + arg0

    # Assert calls without the deprecated argument log nothing.
    with self.assertRaisesRegexp(ValueError, "not present.*\\['missing'\\]"):
      deprecation.deprecated_args(date, instructions, "missing")(_fn)