+ cmd += self._bool_option('--continue-at', 'continuedl', '-', '0')
+ cmd += self._valueless_option('--silent', 'noprogress')
+ cmd += self._valueless_option('--verbose', 'verbose')
+ cmd += self._option('--limit-rate', 'ratelimit')
+ cmd += self._option('--retry', 'retries')
+ cmd += self._option('--max-filesize', 'max_filesize')