@Test
void testIntersect() {

    Samples.assertSetEquals(_Sets.of(), _Sets.intersect(null, null));
    Samples.assertSetEquals(_Sets.of(), _Sets.intersect(null, _Sets.of()));
    Samples.assertSetEquals(_Sets.of(), _Sets.intersect(_Sets.of(), null));
    Samples.assertSetEquals(_Sets.of(), _Sets.intersect(_Sets.of(), _Sets.of()));
    Samples.assertSetEquals(_Sets.of(), _Sets.intersect(_Sets.of(0, 1), _Sets.of(2, 3)));
    Samples.assertSetEquals(_Sets.of(1, 2), _Sets.intersect(_Sets.of(0, 1, 2), _Sets.of(1, 2, 3)));
}