@NotNull
    public MultiMap<AdditionalLibraryRootsProvider, SyntheticLibraryDescriptor> librariesToMap() {
      LOG.assertTrue(libraries != null);
      MultiMap<AdditionalLibraryRootsProvider, SyntheticLibraryDescriptor> result = new MultiMap<>();
      for (SyntheticLibraryDescriptor library : libraries) {
        result.putValue(library.provider, library);
      }
      return result;
    }
@NotNull
    public MultiMap<AdditionalLibraryRootsProvider, SyntheticLibraryDescriptor> librariesToMap()