log_pseudolikelihood for GaussianRBM

has the GaussianRBM been tested with MNIST data the same way as the MNIST example for BinaryRBM? When I created a notebook to run a test in the exact same fashion as the example code, it blows up on `# println("log(PL) = ", mean(@time log_pseudolikelihood(rbm, train_x)))` and indeed, in the pseudolikelihood.jl file, there is no signature for `substitution_matrix_sites()` to accept rbm::RBM{<:Gaussian}