def clone_list(self, l):
        l2 = []
        for x in l:
            if x is newstyle_inplace:
                l2.append(newstyle_inplace(x.value))
            elif x is oldstyle_inplace:
                l2.append(oldstyle_inplace(x.value))
            else :
                l2.append(x)
        return l2