code: def _filter_xpath_grouping(xpath):
      
  
      # First remove the first open parentheses
      xpath = xpath[1:]
  
      # Next remove the last closed parentheses
      index = xpath.rfind(')')
      if index == -1:
          raise XpathException("Invalid or unsupported Xpath: %s" % xpath)
      xpath = xpath[:index] + xpath[index + 1:]
      return xpath
docs: This method removes the outer parentheses for xpath grouping.
      The xpath converter will break otherwise.
      Example:
      "(//button[@type='submit'])[1]" becomes "//button[@type='submit'][1]"