public static String rangeKey(long value) {
    return encodeBase62(value, true);
  }
@Test
  public void testLargeRangeKey() {
    Assert.assertEquals("44C92", IdHelper.rangeKey(1000000L));
    Assert.assertEquals("BAzL8n0Y58m7", IdHelper.rangeKey(Long.MAX_VALUE));
    Assert.assertTrue(IdHelper.rangeKey(1000000L).compareTo(IdHelper.rangeKey(Long.MAX_VALUE)) < 0);
  }