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

        //each argument will be a path
        $paths = func_get_args();

        //for each path
        foreach ($paths as $i => $path) {
            //check for type errors
            $argument->test($i + 1, $path, 'string');
            //add to path
            $this->data .= $this->format($path);
        }

        return $this;
    }