https://www.illumos.org/issues/8361 Without this patch in C locale Python considers 0xa0 a space --- Python-2.7.13/Lib/string.py.1 2017-06-10 03:33:29.959804221 +0000 +++ Python-2.7.13/Lib/string.py 2017-06-10 03:34:10.073176206 +0000 @@ -527,7 +527,7 @@ # that match 's definitions. try: - from strop import maketrans, lowercase, uppercase, whitespace + from strop import maketrans, lowercase, uppercase letters = lowercase + uppercase except ImportError: pass # Use the original versions