Observer::OnMove(nsIRDFResource* aOldSource,
Observer::OnMove(nsIRDFDataSource* aDataSource, nsIRDFResource* aOldSource,
Observer::OnMove(nsIRDFResource* aOldSource,                 nsIRDFResource* aNewSource,                 nsIRDFResource* aProperty,                 nsIRDFNode* aTarget){    nsresult rv;    rv = rdf_WriteOp("mv-from", aOldSource, aProperty, aTarget);    if (NS_FAILED(rv)) return rv;    rv = rdf_WriteOp("mv-to", aNewSource, aProperty, aTarget);    if (NS_FAILED(rv)) return rv;    return NS_OK;}