Dynamic class problem

[Robin Becker]

I'm trying to figure out how to recode a class that is giving a shadow warning under 2.1

the relevant code is

    def __getitem__(self, index):
        try:
            return self._children[index]
        except KeyError:
            Klass = self._prototype
            if Klass in _ItemWrapper.keys():
                WKlass = _ItemWrapper[Klass]
            else:
                class WKlass(Klass):
                    def __getattr__(self,name):
                        try:
                            return Klass.__getattr__(self,name)
                        except:
                            return getattr(self._parent,name)
                _ItemWrapper[Klass] = WKlass

            child = WKlass()
            child._parent = self
            for i in filter(lambda x,K=child.__dict__.keys(): x in K,child._attrMap.keys()):
                del child.__dict__[i]

            self._children[index] = child
            return child


the idea is that I want to generate a child instance based on the _prototype class which has a
single overridden getattr method. This code seemed to be working in 2.0, but I'm getting
warnings now 

c:\python\reportlab\graphics\widgetbase.py:181: SyntaxWarning: local name 'Klass
' in '__getitem__' shadows use of 'Klass' as global in nested scope 'WKlass'
  def __getitem__(self, index):

must I write the inner class as

               class WKlass(Klass):
                   def __getattr__(self,name):
                        try:
                            return WKlass.__bases__[0].__getattr__(self,name)
                        except:
                            return getattr(self._parent,name)

and is that backwards compatible in 2.0?
-- 
Robin Becker