@abc.abstractmethod
    def _get_children(self, path):
Register free parameters, which means their value will not be learned by trainer.
dataset/ETHPy150Open openstack/taskflow/taskflow/persistence/path_based.py/PathBasedConnection._get_children--crossover with--dataset/ETHPy150Open zomux/deepy/deepy/layers/layer.py/NeuralLayer.register_free_parameters