Where is the result of sum?

Question

I want to sum a field tiempo_acumulado for each tarea_id. I try this but dont work, is wrong or how can do this.

foreach ($idstareas as $idtarea)
    {    
    $sumatorio = $this->ProyectosCategoriasTareas->find();
    $sumatorio
        ->select(['suma' => $sumatorio->func()->sum('tiempo_acumulado')])
        ->where(['tarea_id'=>$idtarea->id])
        ->toArray();
    debug($sumatorio);
    die();
    }

I dont find suma or the result

Answer 1

This work! for me

foreach ($idstareas as $idtarea)
    {    
    $arrayTareas = $this->ProyectosCategoriasTareas->find('all')->where(['tarea_id'=>$idtarea->id]);
    $collection = new Collection($arrayTareas);
    $sumDeHoras = $collection->sumOf('tiempo_acumulado');
    debug($sumDeHoras);
    die();
    }