nsClassList& operator=(const nsClassList& aClassList) { return *this; }
nsClassList& operator=(const nsClassList& aClassList) { if (this != &aClassList) { delete mNext; mNext = nsnull; mAtom = aClassList.mAtom;  if (aClassList.mNext) { mNext = new nsClassList(*(aClassList.mNext)); } } return *this; }
    nsClassList& operator=(const nsClassList& aClassList) { return *this; } // not to be implemented