Issue 22603: add missing 'self'. Patch by Francisco Fernández Castaño.

Doc/library/contextlib.rst

@@ -568,10 +568,10 @@ single definition::
             self.name = name
 
         def __enter__(self):
-            logging.info('Entering: {}'.format(name))
+            logging.info('Entering: {}'.format(self.name))
 
         def __exit__(self, exc_type, exc, exc_tb):
-            logging.info('Exiting: {}'.format(name))
+            logging.info('Exiting: {}'.format(self.name))
 
 Instances of this class can be used as both a context manager::