How to convert checkboxlist into radio list

Here is my forum which is using checkbox list but when I am using radio list it is showing error What was there already.

 <?= $form->field($model,'checklist')->checkboxList([ 'advertisers' => 'advertisers', 'publisher' => 'publisher']); ?>

What I have tried

<?= $form->field($model,‘checklist’)->radioList([ ‘advertisers’ => ‘advertisers’, ‘publisher’ => ‘publisher’]); ?>

I am getting output but after I submitted the forum throwing an error

An invalid value is supplied for each

$permissionList = $_POST['SignupForm']['checklist'];

        foreach ($permissionList as $value) {

          $newPermission = new AuthAssignment;

          $newPermission->user_id = $user->id;

          $newPermission->item_name = $value;




Where am i going wrong?

Check the values you are getting with var_dump($_POST[‘SignupForm’][‘checklist’]).

I am getting

string(9) "publisher" 

also advertiser as well If i use check box list the var_dump returning

array(1) { [0]=> string(11) "advertisers" }

$permissionList[] = $_POST[‘SignupForm’][‘checklist’];

Adding this solved the problem.