/**
  * @param \Drupal\Core\Url $url
  *   The URL associated with an operation.
  *
  * @param $migration_group
  *   The migration's parent group.
  */
 protected function addGroupParameter(Url $url, $migration_group)
 {
     $route_parameters = $url->getRouteParameters() + array('migration_group' => $migration_group);
     $url->setRouteParameters($route_parameters);
 }
 /**
  * @param \Drupal\Core\Url $url
  *   The URL associated with an operation.
  *
  * @param $migration_group
  *   The migration's parent group.
  */
 protected function addGroupParameter(Url $url, $migration_group)
 {
     if (!$migration_group) {
         $migration_group = 'default';
     }
     $route_parameters = $url->getRouteParameters() + ['migration_group' => $migration_group];
     $url->setRouteParameters($route_parameters);
 }