code: def online_help(param=None):
      
      try:
          PARAMS_LINK_KEYS = sorted(PARAMS_LINK.keys())
          if param in PARAMS_LINK_KEYS:
              webbrowser.open_new_tab(DOCUMENT_ADR + PARAMS_LINK[param])
          elif param in range(1, len(PARAMS_LINK_KEYS) + 1):
              webbrowser.open_new_tab(
                  DOCUMENT_ADR + PARAMS_LINK[PARAMS_LINK_KEYS[param - 1]])
          else:
              print("Please choose one parameter : \n")
              print('Example : online_help("J") or online_help(2)\n')
              for index, item in enumerate(PARAMS_LINK_KEYS):
                  print(str(index + 1) + "-" + item)
      except Exception:
          print("Error in online help")
docs: Open online document in web browser.
  
      :param param: input parameter
      :type param : int or str
      :return: None