RWMB_Input_Field::normalize PHP Method

    public static function normalize($field)
    {
        $field = parent::normalize($field);
        $field = wp_parse_args($field, array('datalist' => false, 'readonly' => false));
        if ($field['datalist']) {
            $field['datalist'] = wp_parse_args($field['datalist'], array('id' => $field['id'] . '_list', 'options' => array()));
        }
        return $field;
    }

 /**
  * Normalize parameters for field
  *
  * @param array $field
  *
  * @return array
  */
 static function normalize($field)
 {
     $field = parent::normalize($field);
     $field = wp_parse_args($field, array('flatten' => true, 'query_args' => array(), 'field_type' => 'select'));
     if ('checkbox_tree' === $field['field_type']) {
         $field['field_type'] = 'checkbox_list';
         $field['flatten'] = false;
     }
     switch ($field['field_type']) {
         case 'checkbox_list':
         case 'radio_list':
             $field['flatten'] = 'radio_list' === $field['field_type'] ? true : $field['flatten'];
             $field['multiple'] = 'radio_list' === $field['field_type'] ? false : true;
             $field = RWMB_Input_Field::normalize($field);
             break;
         case 'select_advanced':
             $field = RWMB_Select_Advanced_Field::normalize($field);
             $field['flatten'] = true;
             break;
         case 'select_tree':
             $field = RWMB_Select_Field::normalize($field);
             $field['multiple'] = true;
             break;
         case 'select':
         default:
             $field = RWMB_Select_Field::normalize($field);
             break;
     }
     return $field;
 }