The Drush integration with Devel Generate is broken

[juampynr]

This is what happens when you attempt to generate redirects using Drush:

juampy@Juampy/var/www/drupal8(8.1.x)$ drush generate-redirects 5
PHP Fatal error:  Call to undefined function drush_generate_is_number() in /var/www/drupal8/modules/contrib/redirect/redirect.drush.inc on line 30
PHP Stack trace:
PHP   1. {main}() /usr/share/drush/drush.php:0
PHP   2. drush_main() /usr/share/drush/drush.php:12
PHP   3. Drush\Boot\BaseBoot->bootstrap_and_dispatch() /usr/share/drush/includes/preflight.inc:66
PHP   4. drush_dispatch() /usr/share/drush/lib/Drush/Boot/BaseBoot.php:67
PHP   5. call_user_func_array:{/usr/share/drush/includes/command.inc:185}() /usr/share/drush/includes/command.inc:185
PHP   6. drush_command() /usr/share/drush/includes/command.inc:185
PHP   7. _drush_invoke_hooks() /usr/share/drush/includes/command.inc:217
PHP   8. call_user_func_array:{/usr/share/drush/includes/command.inc:366}() /usr/share/drush/includes/command.inc:366
PHP   9. drush_redirect_generate_redirects() /usr/share/drush/includes/command.inc:366
Drush command terminated abnormally due to an unrecoverable error.                                                                                                   [error]
Error: Call to undefined function drush_generate_is_number() in /var/www/drupal8/modules/contrib/redirect/redirect.drush.inc, line 30