SF 563203. Replaced 'has_key()' with 'in'.
diff --git a/Lib/regsub.py b/Lib/regsub.py
index a86819f..9b8fae5 100644
--- a/Lib/regsub.py
+++ b/Lib/regsub.py
@@ -134,7 +134,7 @@
     if type(pat) != type(''):
         return pat              # Assume it is a compiled regex
     key = (pat, regex.get_syntax())
-    if cache.has_key(key):
+    if key in cache:
         prog = cache[key]       # Get it from the cache
     else:
         prog = cache[key] = regex.compile(pat)