Add rsplit method for UserString, too.

(Spotted by Raymond Hettinger)

Lib/UserString.py

@@ -113,6 +113,8 @@ class UserString:
     def rstrip(self, chars=None): return self.__class__(self.data.rstrip(chars))
     def split(self, sep=None, maxsplit=-1):
         return self.data.split(sep, maxsplit)
+    def rsplit(self, sep=None, maxsplit=-1):
+        return self.data.rsplit(sep, maxsplit)
     def splitlines(self, keepends=0): return self.data.splitlines(keepends)
     def startswith(self, prefix, start=0, end=sys.maxint):
         return self.data.startswith(prefix, start, end)