return NS_OK;
  void RegisterDTD(nsIDTD* aDTD){    if(aDTD) {      NS_ADDREF(aDTD);      CDTDFinder theFinder(aDTD);      if(!mDTDDeque.FirstThat(theFinder)) {        nsIDTD* theDTD;        aDTD->CreateNewInstance(&theDTD);        mDTDDeque.Push(theDTD);      }      NS_RELEASE(aDTD);    }  }