python2 pip build fails, due to wrong version information (see inside for solution)

[alex-quin-gabriel]

numpy==1.16.5
scipy==1.0.1
matplotlib==2.2.4

Adding these version numbers in python2/requirements.txt worked for me. Apparently projects have moved on to python3, these are the latest versions compiling with pip2 for the respective projects.
I also had to adjust the toulbar version to from 0.9.8.0 to 0.9.7.0 in python2/pracmln/wcsp/wcsp.py.