def test_merge(self):
DATA0 = ['one', 'two', 'three', 'four']
DATA1 = ['one', 'three', 'five', 'seven']
c = Classes(DATA0)
c.merge(DATA1)
assert len(c) == 6
assert c[:4] == DATA0
assert c[4] == DATA1[2]
assert c[5] == DATA1[3]
