@Theory
 public void test_isNotIn_assertion(ZonedDateTime referenceDate) {
   // WHEN
   assertThat(referenceDate)
       .isNotIn(referenceDate.plusNanos(1).toString(), referenceDate.plusNanos(2).toString());
   // THEN
   verify_that_isNotIn_assertion_fails_and_throws_AssertionError(referenceDate);
 }
 private static void verify_that_isNotIn_assertion_fails_and_throws_AssertionError(
     ZonedDateTime reference) {
   try {
     assertThat(reference).isNotIn(reference.toString(), reference.plusNanos(1).toString());
   } catch (AssertionError e) {
     // AssertionError was expected
     return;
   }
   fail("Should have thrown AssertionError");
 }