QBankApi.php
public function folders()
    {
        if (!$this->folders instanceof FoldersController) {
            $this->folders = new FoldersController($this->getClient(), $this->cachePolicy, $this->cache);
            $this->folders->setLogger($this->logger);
        }

        return $this->folders;
    }
public function folders()
    {
        if (!$this->folders instanceof FoldersController) {
            $this->folders = new FoldersController($this->getClient(), $this->cachePolicy, $this->cache);
            $this->folders->setLogger($this->logger);
        }

        return $this->folders;
    }
Folders are used to group Media in a hierarchial manner.

@return FoldersController