private static @NotNull HierarchicalMethodSignatureImpl copy(@NotNull HierarchicalMethodSignature hi) {
    HierarchicalMethodSignatureImpl hierarchicalMethodSignature = new HierarchicalMethodSignatureImpl(hi);
    for (HierarchicalMethodSignature his : hi.getSuperSignatures()) {
      hierarchicalMethodSignature.addSuperSignature(copy(his));
    }
    return hierarchicalMethodSignature;
  }
private static @NotNull HierarchicalMethodSignatureImpl copy(@NotNull HierarchicalMethodSignature hi)