@Override
  public Reiterator<Object> get(int tag) {
    return new SubIterator(tag);
  }
@Test
  public void testNextIteration() {
    TaggedReiteratorList iter = create(2, new String[] {"a", "b", "c"});
    Reiterator<?> get0 = iter.get(0);
    assertEquals(get0, "a0", "b0", "c0");
    Iterator<?> get1 = iter.get(1);
    Assert.assertEquals("a1", get1.next());
    assertEquals(get0.copy() /*empty*/);
    Assert.assertEquals("b1", get1.next());
    assertEquals(iter.get(1), "a1", "b1", "c1");
  }