@Test
    public void testContains() {
        assertTrue(Seq.of(1, 2, 3).contains(2));
        assertFalse(Seq.of(1, 2, 3).contains(4));
        assertFalse(Seq.of(1, 2, 3).contains(null));
    }
@author Lukas Eder
@author Roman Tkalenko
jOOL-java-8/src/test/java/org/jooq/lambda/SeqTest.java