[graph-tool] eweight vs. recs in BlockState

Dear list, what exactly does the 'recs' (and rec_types) parameter in 'BlockState' and 'LayeredBlockState' do? I couldn't find an example in the documentation. But for instance if I have a network with integer edge weights (stored in the PropertyMap 'weight'), I could specify recs=[weight], rec_types=["discrete-poisson"]. And probably that would assume a Poisson distribution for the weights; am I right? If I am, then would this be the same as specifying eweight=weight and deg_corr=False? Many thanks in advance, Peter