Why can't I use PyMLNs engine in mlnlearn tool？

[MRSHIMMER]

I try to follow this tutorial (https://github.com/opcode81/ProbCog/wiki/MLN-Tutorial). However, when using the mlnlearn tool, I can't use the PyMLNs engine. Among the options, there is only the internal engine. If the default internal engine is used, I will add the default weight 0 before the rule as specified in the tutorial, but the inferred weight will be 0. I want to know how to solve it.

Thanks a lot!