private function getFolderByVolumeId(int $volumeId): VolumeFolder
    {
        return $this->mockFolder ? $this->mockFolder : VolumeFolder::findOne(['volumeId' => $volumeId]);
    }
private function getFolderByVolumeId(int $volumeId): VolumeFolder
    {
        return $this->mockFolder ? $this->mockFolder : VolumeFolder::findOne(['volumeId' => $volumeId]);
    }
private function getFolderByVolumeId ( int $ volumeId ) : VolumeFolder { return $ this -> mockFolder ? $ this -> mockFolder : VolumeFolder :: findOne ( [ 'volumeId' => $ volumeId ] ) ; }
Get folder by volume id

@param int $volumeId
@return VolumeFolder
Get folder by volume id