private @Nullable String getFirstModuleRoot() {
    final Module module = getModule();
    if (module == null) {
      return null;
    }
    final VirtualFile[] roots = ModuleRootManager.getInstance(module).getContentRoots();
    return roots.length > 0 ? roots[0].getPath() : null;
  }
private @Nullable String getFirstModuleRoot()