public ChildNumber getChildNumber() {
        return childNumberPath.size() == 0 ? ChildNumber.ZERO : childNumberPath.get(childNumberPath.size() - 1);
    }
public ChildNumber getChildNumber ( ) { return childNumberPath . size ( ) == 0 ? ChildNumber . ZERO : childNumberPath . get ( childNumberPath . size ( ) - 1 ) ; }
Returns the last element of the path returned by {@link DeterministicKey#getPath()}