public void isNotEmpty() {
    if (checkNotNull(actual).isEmpty()) {
      failWithoutActual(simpleFact("expected not to be empty"));
    }
  }
@Test
  public void tableIsNotEmptyWithFailure() {
    ImmutableTable<Integer, Integer, Integer> table = ImmutableTable.of();
    expectFailureWhenTestingThat(table).isNotEmpty();
    assertFailureKeys("expected not to be empty");
  }