public void toggleMarkingAsNamespacePackage(@NotNull VirtualFile directory) {
    SideEffectGuard.checkSideEffectAllowed(SideEffectGuard.EffectType.SETTINGS);
    if (!directory.isDirectory()) return;

    if (canBeMarked(directory)) {
      myNamespacePackageFolders.add(directory);
      PyNamespacePackagesStatisticsCollector.logToggleMarkingAsNamespacePackage(true);
    }
    else if (isMarked(directory)) {
      myNamespacePackageFolders.remove(directory);
      PyNamespacePackagesStatisticsCollector.logToggleMarkingAsNamespacePackage(false);
    }
    else {
      throw new IllegalStateException("Can't toggle namespace package state for: " + directory.getName());
    }

    refreshView();
  }
public void toggleMarkingAsNamespacePackage(@NotNull VirtualFile directory)