docs: public static /*@Nullable*/String getParent(String path)
      {
          if (path == null) throw new IllegalArgumentException("'path' can't be null");
          if (path.length() == 0) return null;
          if (!path.startsWith("/")) throw new IllegalArgumentException("Not a valid path.  Doesn't start with a \"/\": \"" + path + "\"");
          if (path.endsWith("/")) throw new IllegalArgumentException("Not a valid path.  Ends with a \"/\": \"" + path + "\"");
  
          int lastSlash = path.lastIndexOf("/");
          return path.substring(0, lastSlash);
      }