'Combine items in both lists
removing duplicates.'

def test_union_items(self):

    listA = [1, 2, 3, 4, 5, 8, 9]
    listB = [1, 2, 3, 4, 5, 6, 7]
    want = [1, 2, 3, 4, 5, 6, 7, 8, 9]
    got = _union_items(listA, listB)
    self.assertEqual(want, got)
