*
     * E.g.
     *   (some, some/path) -> path
     *   (some, some/path/othere) -> path/other
     *   (C:, '') -> C:
     */
    public String pathToChild(String relativeChildPath) {
        return isEmpty()
            ? relativeChildPath
            : relativeChildPath.substring(length() + 1);
    }

    /**