@VisibleForTesting
  static <T extends Comparable<? super T>> boolean le(T a, T b) {
    return a.compareTo(b) <= 0;
  }
@Test
  public void testComparators_LE() {
    Assert.assertTrue(VersionChecker.le(0, 1));
    Assert.assertTrue(VersionChecker.le(1, 1));
    Assert.assertFalse(VersionChecker.le(2, 1));
  }