code: @Nullable
    public static String stripBidi (@Nullable final String sStr)
    {
      if (sStr == null || sStr.length () <= 1)
        return sStr;
  
      String ret = sStr;
      if (isBidi (ret.charAt (0)))
        ret = ret.substring (1);
      if (isBidi (ret.charAt (ret.length () - 1)))
        ret = ret.substring (0, ret.length () - 1);
      return ret;
    }
docs: Removes leading and trailing bidi controls from the string
  
  @param sStr
  Source string
  @return the modified string