private static @NotNull Set<VirtualFile> getModuleRoots(@Nullable Project project) {
    if (project != null) {
      final Set<VirtualFile> moduleRoots = new HashSet<>();
      final Module[] modules = ModuleManager.getInstance(project).getModules();
      for (Module module : modules) {
        moduleRoots.addAll(PyUtil.getSourceRoots(module));
      }
      return moduleRoots;
    }
    return Collections.emptySet();
  }
private static @NotNull Set<VirtualFile> getModuleRoots(@Nullable Project project)