function y = sample_node(CPD, pev)% SAMPLE_NODE Draw a random sample from P(Y|pa(y), theta)  (root)% Y = SAMPLE_NODE(CPD, PEV)%% pev{i} is the evidence on the i'th parent.% Since a root has no parents, we ignore pev,% and return the value the root was clamped to when it was created.y = CPD.val;