Fix some Python warnings about unknown/unnecessary string escape sequences.
Fix some Python warnings about unknown/unnecessary string escape sequences.

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