Method ch

test/test_runon.py:299–302

(a)

        self.assertEqual(r.sum(), [2, 3, 4])

        def ch(a):
            def _ch(ro):
                ro / (lambda p: p.update(p.v + a))
            return _ch

        r = Runon(1, 2, 3)
        r | ch(2)