st1.mix(m0).step()
me.assertNotEqual(st0.extract(32), st1.extract(32))
+ ## Check state copying.
+ st1 = st0.copy()
+ mask = st1.extract(len(m1))
+ st0.mix(m1)
+ st1.mix(m1)
+ me.assertEqual(st0.extract(32), st1.extract(32))
+
## Check error conditions.
_ = st0.extract(200)
me.assertRaises(ValueError, st0.extract, 201)