public function delete($request)
    {
        $entriesCleared = 0;

        if ($this->exists($request)) {
            foreach ($this->entries as $entry) {
                if ($entry['cacheData']) {
                    // delete each results of the manifest
                    if ($this->cache->delete($entry['cacheData'])) {
                        $entriesCleared++;
                    }
                }
            }
            // delete the manifest of data source
            $this->cache->delete($this->key);
        }
        return $entriesCleared;
    }