NS_NOTYETIMPLEMENTED("write me!"); return NS_ERROR_NOT_IMPLEMENTED;
NS_PRECONDITION(aFirstChild != nsnull, "null ptr"); if (! aFirstChild) return NS_ERROR_NULL_POINTER;  if (mRootContent) { return mRootContent->QueryInterface(nsIDOMNode::GetIID(), (void**) aFirstChild); } else { *aFirstChild = nsnull; return NS_OK; }
XULDocumentImpl::GetFirstChild(nsIDOMNode** aFirstChild){    NS_NOTYETIMPLEMENTED("write me!");    return NS_ERROR_NOT_IMPLEMENTED;}