How do RGCN pass message from relation and inv_relation

Hi, Great Library which helps me a lot, One question about the message passing in RGCN, the inverse relations are added when building a graph, And it seems your implement pass the message from the neighbor entities to center entity from a relation and its inverse relation, which makes a knowledge graph to be an undirected graph. It seems a little odd and a little different from the paper of RGCN???
Look forward for your timely reply!

I’m not the author(@lingfan) of RGCN but I found there’s comment at

And at the footnote 1 at page 2 of also mentioned this. Inverse edge is also added to the graph, but indicating an inverse relation.