private static @NotNull List<VirtualFile> buildSdkPaths(@NotNull Sdk sdk,
                                                          @NotNull List<VirtualFile> sdkRoots,
                                                          @NotNull List<VirtualFile> userAddedRoots) {
    return ImmutableList.<VirtualFile>builder()
      .addAll(sdkRoots)
      .addAll(getSkeletonsPaths(sdk))
      .addAll(userAddedRoots)
      .addAll(PyTypeShed.INSTANCE.findRootsForSdk(sdk))
      .build();
  }
private static @NotNull List<VirtualFile> buildSdkPaths(@NotNull Sdk sdk,
                                                          @NotNull List<VirtualFile> sdkRoots,
                                                          @NotNull List<VirtualFile> userAddedRoots)