Cakephp 3 - isEmpty example

isempty.php

    public function index($sliderId = null)
    {
        $exists = $this->Slides->Sliders->exists(['id' => $sliderId]);
        if (!$exists) {
            throw new RecordNotFoundException(__('Cannot find the provided slider'));
        }
        $this->paginate = [
            'contain' => ['Sliders']
        ];
        $query = $this->Slides
            ->find('all', [
                'contain' => [
                    'SlideImages' => [
                        'sort' => [
                            'created' => 'DESC'
                        ]
                    ]
                ]
            ])
            ->where(['slider_id' => $sliderId]);
        // if ($query->isEmpty()) {
        //     $this->Flash->set(__('No slides were found. Please add one.'));
        //     return $this->redirect(['action' => 'add', $sliderId]);
        // }
        $slides = $this->paginate($query);
        $this->set(compact('slides'));
        $this->set('_serialize', ['slides']);