another routing problem :) please help

for testin I do:
public function wpis($id=0)


and add in Routes
$routes->get('/wpis', 'FRONT\Blog:wpis');
$routes->get('/wpis/(:num)', 'FRONT\Blog::wpis/$1');

now, in url when I go in:
https://url/wpis

i get:
ErrorException
Undefined array key 1
SYSTEMPATH/Router/Router.php at line 430

strange things

below stil not works
$routes->get('/wpis/(:num)', 'FRONT\Blog::wpis/$1');