random module differences between Pyhton 2.x and Python 3.x

[baugetfa]

All simulations with existing roots give same results in Py2 and Py3.
This is not the case with root generation with a given seed. It seems that it comes from the module "random". For instance, with the same seed, random.expovariate() or random.randint() do not give the same result. I tried to add the argument "version" in random.seed() without any change.
WIP