public static ImmutableList<ChildNumber> concat(List<ChildNumber> path, List<ChildNumber> path2) {
        return ImmutableList.<ChildNumber>builder().addAll(path).addAll(path2).build();
    }
public static ImmutableList < ChildNumber > concat ( List < ChildNumber > path , List < ChildNumber > path2 ) { return ImmutableList . < ChildNumber > builder ( ) . addAll ( path ) . addAll ( path2 ) . build ( ) ; }
Concatenate two derivation paths