code: def as_decorator(mcs, cls):
          
          return mcs(cls.__name__, cls.__bases__, cls.__dict__.copy())
docs: Use :class:`Singleton` as a decorator for Python 2/3 compatibility::
  
              @Singleton.as_decorator
              class SingletonType(object):
                  def __repr__(self):
                      return 'singleton'
  
              singleton = SingletonType()
  
          :param cls: Class to become a singleton
          :type cls: type
          :return: The new singleton
          :rtype: Singleton