Python singleton pattern

After a quick search where I didn’t find a singleton implementation for new-style classes in Python. For classic classes there’s the excellent Borg pattern. So here’s singleton for new-style classes:

class Singleton(object):

      __instance = None

      @classmethod
      def getInstance(cl):
          """
          Get the global engine instance or create one if none exists yet.
          """
          if cl.__instance is None:
              cl.__instance = cl()

          return cl.__instance