public function writeCrop($path, $contents) {
        try {
            $this->getCropsDisk()->write($path, $contents);
        } catch(FileExistsException $e) {
            throw new Exception("Croppa: Crop already exists at $path. You probably
                have a misconfiguration. Make sure that the URL to your crop can be
                transformed by the `path` config to your `crop_dir`.");
        }

    }