SPM Bayesian model estimation -> contrast estimation 1st level

I want to run spm.EstimateModle() using .estimation_method = {'Bayesian': 1}. While looking at the EstimateContrast() node docs I didn’t see any way for it to take Cbeta*.nii files and compute posterior probability maps. I can only pass betas to it and compute T or F contrasts. Is this not implemented yet?