public function removeFiles($regex = null)
    {
        //argument 1 must be a string
        Argument::i()->test(1, 'string', 'null');

        //get the files
        $files = $this->getFiles($regex);

        if (empty($files)) {
            return $this;
        }

        //walk the array
        foreach ($files as $file) {
            //remove everything
            $file->remove();
        }

        return $this;
    }