PEP-0318, @decorator-style. In Guido's words:

"@ seems the syntax that everybody can hate equally"
Implementation by Mark Russell, from SF #979728.

Tools/compiler/regrtest.py

@@ -47,6 +47,8 @@ def compile_files(dir):
                 continue
             # make sure the .pyc file is not over-written
             os.chmod(source + "c", 444)
+        elif file == 'CVS':
+            pass
         else:
             path = os.path.join(dir, file)
             if os.path.isdir(path):