Sample function of Bayesian network

[yfpeng1234]

Dear author, I found there might be a bug in Bayesian network's sample function. For the above structure, assuming that the distribution list is ['c', 'a', 'b']: so firstly we will sample for node 'c', but we don't have value of 'a' and 'b', then we will sample for 'a' and 'b'. Finally we will not get the value of 'c' am I right?