code: public function possibleSections()
      {
          $s = ['' => '(self)'];
          foreach (Yii::$app->collectors['sections']->getAll() as $section) {
              $s[$section->systemId] = $section->sectionTitle;
          }
  
          return $s;
      }
docs: [[@doctodo method_description:possibleSections]].
  
  @return [[@doctodo return_type:possibleSections]] [[@doctodo return_description:possibleSections]]