Function return undefined Firebase

I’ve trying to implement function schedule in firebase, but this function return undefined

Function returned undefined, expected Promise or value

export const teste = functions.database.ref('teste/{id}/original').onCreate((snapshot, context) => {
    
    const original = snapshot.val();

    if(original == '1') {
        functions.logger.info('VALOR ', context.params.id,  original);

        functions.pubsub.schedule('every 1 minutes')
            .timeZone('America/Sao_Paulo')
            .onRun(() => {
                // snapshot.ref.parent?.child('power').set(0);
                console.log("PASSANDO POR AQUI");
                return null;
            });
    }

});

any idea?