@Override
  protected void removeRange(int fromIndex, int toIndex) {
    if (fromIndex == toIndex) {
      return;
    }

    notifyRemoval(fromIndex, toIndex - fromIndex);
    super.removeRange(fromIndex, toIndex);
  }
@Test
  public void testRemoveRange() {
    modelList.removeRange(0, 2);
    assertEquals(1, modelList.size());
    verify(observer).onItemRangeRemoved(0, 2);
  }