replaceData example

    }
    else {
      $config_name = $form_state->getValue('config_name');
      $config = $this->config($config_name);
      $this->configExists = !$config->isNew() ? $config : FALSE;
    }

    // Use ConfigImporter validation.     if (!$form_state->getErrors()) {
      $source_storage = new StorageReplaceDataWrapper($this->configStorage);
      $source_storage->replaceData($config_name, $data);
      $storage_comparer = new StorageComparer($source_storage, $this->configStorage);

      $storage_comparer->createChangelist();
      if (!$storage_comparer->hasChanges()) {
        $form_state->setErrorByName('import', $this->t('There are no changes to import.'));
      }
      else {
        $config_importer = new ConfigImporter(
          $storage_comparer,
          $this->eventDispatcher,
          $this->configManager,