public static <T> Iterable<T> nullToEmpty(Iterable<T> iterable) {
        return iterable == null ? Collections.emptyList() : iterable;
    }
@Test
    public void testIterableIsEmpty_whenNullUsed() {
        assertEquals(emptyList(), IterableUtil.nullToEmpty(null));
        assertEquals(numbers, IterableUtil.nullToEmpty(numbers));
    }