SF 563203. Replaced 'has_key()' with 'in'.
diff --git a/Lib/sre_parse.py b/Lib/sre_parse.py
index 1aba456..a5a8831 100644
--- a/Lib/sre_parse.py
+++ b/Lib/sre_parse.py
@@ -568,9 +568,9 @@
                     continue
                 else:
                     # flags
-                    if not FLAGS.has_key(source.next):
+                    if not source.next in FLAGS:
                         raise error, "unexpected end of pattern"
-                    while FLAGS.has_key(source.next):
+                    while source.next in FLAGS:
                         state.flags = state.flags | FLAGS[source.get()]
             if group:
                 # parse group contents