Sulu\Bundle\MediaBundle\Collection\Manager\CollectionManagerInterface::save PHP Method

    public function save($data, $userId);

 /**
  * Creates a new collection.
  *
  * @param string $title
  * @param string $key
  * @param string $locale
  * @param int $userId
  * @param int|null $parent id of parent collection or null for root
  * @param int|null $id if not null a colleciton will be updated
  *
  * @return Collection
  */
 private function createCollection($title, $key, $locale, $userId, $parent = null, $id = null)
 {
     $data = ['title' => $title, 'key' => $key, 'type' => ['id' => 2], 'locale' => $locale];
     if ($parent !== null) {
         $data['parent'] = $parent;
     }
     if ($id !== null) {
         $data['id'] = $id;
     }
     return $this->collectionManager->save($data, $userId);
 }