Index: Lib/sre_parse.py
===================================================================
--- Lib/sre_parse.py	(revision 62337)
+++ Lib/sre_parse.py	(working copy)
@@ -568,6 +568,27 @@
                             raise error, "unknown group name"
                         subpatternappend((GROUPREF, gid))
                         continue
+                    elif sourcematch("#"):
+                        # Python-Specific Comment -- allows for nested
+                        # paren
+                        depth = 1
+                        while 1:
+                            if sourcematch("\\"):
+                                # Ignore escaped characters
+                                if not source.next:
+                                    break
+                            elif source.next == "(":
+                                depth += 1
+                            elif source.next == ")":
+                                depth -= 1
+                                if not depth:
+                                    break
+                            if source.next is None:
+                                break
+                            sourceget()
+                        if not sourcematch(")"):
+                            raise error, "unbalanced parenthesis"
+                        continue
                     else:
                         char = sourceget()
                         if char is None: