Tighten a condition to make passing None more explicit.
Tighten a condition to make passing None more explicit.

da-woods/cython,cython/cython,scoder/cython,scoder/cython,da-woods/cython,da-woods/cython,cython/cython,da-woods/cython,scoder/cython,cython/cython,cython/cython,scoder/cython