def test_required(self):
        class TForm(yota.Form):
            t = ListNode()

        test = TForm()
        self.assertRaises(InvalidContextException, test.render)
Add. Returns new ParamBag, with fields equal to self + PB
dataset/ETHPy150Open icook/yota/src/yota/tests/test_nodes.py/TestNode.test_required--crossover with--dataset/ETHPy150Open daeilkim/refinery/refinery/bnpy/bnpy-dev/bnpy/suffstats/ParamBag.py/ParamBag.__add__