def __str__(self):
        l = self.u[0]
        return ("%s ~ Categorical(lambda)\n"
                "  lambda =\n"
                "%s\n"
                % (self.name, l))
Remove unconnected variable nodes
dataset/ETHPy150Open bayespy/bayespy/bayespy/inference/vmp/nodes/poisson.py/Poisson.__str__--crossover with--dataset/ETHPy150Open OpenMDAO/OpenMDAO-Framework/openmdao.main/src/openmdao/main/depgraph.py/DependencyGraph.prune_unconnected_vars