Avoid scipy 1.3 breaking factorial import path

[jonringer]

Noticed this was broken on nixpkgs/master because of an update to scipy.

In scipy 1.3, they removed scipy.misc.factorial and instead, only scipy.math.factorial remains.

Because math is just a class, and not a module, I couldn't emulate a similar from ... import factorial :(

[FRidh]

Thank you.

[FRidh]

Requiring 1.3 is actually not acceptable. I merged it without considering that. Due to another change I force-pushed removing the commit.

[jonringer]

I should have added that I was able to pass your test suite with 1.2.1. I think the scipy.misc module was never meant to be stable.

But your changes seem to make this irrelevant.

scipy is just re-exporting stuff from numpy, so if you really wanted to, you could just change it to

from numpy import math
factorial = math.factorial

and I'm assuming that would be more stable. But I haven't really used either, so what do i know :)