public function help($width = 0)
    {
        $default = $short = '';
        if ($this->_default && $this->_default !== true) {
            $default = sprintf(' <comment>(default: %s)</comment>', $this->_default);
        }
        if ($this->_choices) {
            $default .= sprintf(' <comment>(choices: %s)</comment>', implode('|', $this->_choices));
        }
        if (strlen($this->_short) > 0) {
            $short = ', -' . $this->_short;
        }
        $name = sprintf('--%s%s', $this->_name, $short);
        if (strlen($name) < $width) {
            $name = str_pad($name, $width, ' ');
        }

        return sprintf('%s%s%s', $name, $this->_help, $default);
    }