@NotNull
  static List<NestingRule> loadDefaultNestingRules() {
    List<NestingRule> result = new ArrayList<>();

    final ProjectViewNestingRulesProvider.Consumer consumer = (parentFileSuffix, childFileSuffix) -> {
      LOG.assertTrue(!parentFileSuffix.isEmpty() && !childFileSuffix.isEmpty(), "file suffix must not be empty");
      LOG.assertTrue(!parentFileSuffix.equals(childFileSuffix), "parent and child suffixes must be different: " + parentFileSuffix);
      result.add(new NestingRule(parentFileSuffix, childFileSuffix));
    };

    for (ProjectViewNestingRulesProvider provider : EP_NAME.getExtensionList()) {
      provider.addFileNestingRules(consumer);
    }

    return result;
  }
@NotNull
  static List<NestingRule> loadDefaultNestingRules()