remove trailing ws

pep-0008.txt

@@ -967,13 +967,13 @@ Programming Recommendations
 - Use ``is not`` operator rather than ``not ... is``.  While both
   expressions are functionally identical, the former is more readable
   and preferred.
-  
+
   Yes::
-  
+
       if foo is not None:
-      
+
   No::
-  
+
       if not foo is None:
 
 - When implementing ordering operations with rich comparisons, it is