code: public static function getGroupAssigmentOptions($optionName, $individualGroupAssignmentOptions = null) {
          //try object specific settings
          if ($individualGroupAssignmentOptions != null &&
              is_array($individualGroupAssignmentOptions) && 
              array_key_exists($optionName, $individualGroupAssignmentOptions)) 
          {
              return $individualGroupAssignmentOptions[$optionName];
          }
          
          //try yii2 params
          else if (isset(Yii::$app->params['LDAP-Group-Assignment-Options']) &&
              is_array(Yii::$app->params['LDAP-Group-Assignment-Options']) && 
              array_key_exists($optionName, Yii::$app->params['LDAP-Group-Assignment-Options'])) 
          {
              return Yii::$app->params['LDAP-Group-Assignment-Options'][$optionName];
          }
          
          //default from distribution
          else if (array_key_exists($optionName, static::GROUP_ASSIGNMENT_TOUCH_ONLY_MATCHING_REGEX)) {
              return static::GROUP_ASSIGNMENT_TOUCH_ONLY_MATCHING_REGEX[$optionName];
          } 
          
          //Exception
          else {
              throw new \yii\base\Exception('Group-Option ' . $optionName . ' not found. Please define settings in the config/params.php of the yii2 framework as described on top of the UserDbLdap.php');   
          }
      }
docs: Get a value of the group assignment options by option key.
  The options can be defined with the setIndividualGroupAssignmentOptions
  function of this class for a single object, or global in the yii2 params.php.
  If nothing is defined the defaults from the varibale GROUP_ASSIGNMENT_TOUCH_ONLY_MATCHING_REGEX
  are used.
  
  See function updateGroupAssignment for further explanation.
  
  @param string $optionName The option key of the value to retrive.
  @param string $individualSyncOptions Array with individual group assignment options for this function call only
  @return mixed The value of the option key
  @throws \yii\base\Exception if option key is not found in the given option set.