@Test
public void selectInstancesOf() {
MutableBag<Number> numbers = UnmodifiableBag.of(HashBag.<Number>newBagWith(1, 2.0, 3, 4.0, 5));
Assert.assertEquals(iBag(1, 3, 5), numbers.selectInstancesOf(Integer.class));
Assert.assertEquals(iBag(1, 2.0, 3, 4.0, 5), numbers.selectInstancesOf(Number.class));
}
