code: def addHelpMenu(menuName, parentMenuFunction=None):
      '''
      Adds a help menu to the plugin menu.
      This method should be called from the initGui() method of the plugin
  
      :param menuName: The name of the plugin menu in which the about menu is to be added.
      '''
  
      parentMenuFunction = parentMenuFunction or iface.addPluginToMenu
      namespace = _callerName().split(".")[0]
      path = "file://{}".format(os.path.join(os.path.dirname(_callerPath()), "docs",  "html", "index.html"))    
      helpAction = QtWidgets.QAction(QgsApplication.getThemeIcon('/mActionHelpContents.svg'), 
                                      "Plugin help...", iface.mainWindow())
      helpAction.setObjectName(namespace + "help")
      helpAction.triggered.connect(lambda: openHelp(path))
      parentMenuFunction(menuName, helpAction)
      global _helpActions
      _helpActions[menuName] = helpActiof addHelpMenu(menuName, parentMenuFunction=None):
      '''
      Adds a help menu to the plugin menu.
      This method should be called from the initGui() method of the plugin
  
      :param menuName: The name of the plugin menu in which the about menu is to be added.
      '''
  
      parentMenuFunction = parentMenuFunction or iface.addPluginToMenu
      namespace = _callerName().split(".")[0]
      path = "file://{}".format(os.path.join(os.path.dirname(_callerPath()), "docs",  "html", "index.html"))    
      helpAction = QtWidgets.QAction(QgsApplication.getThemeIcon('/mActionHelpContents.svg'), 
                                      "Plugin help...", iface.mainWindow())
      helpAction.setObjectName(namespace + "help")
      helpAction.triggered.connect(lambda: openHelp(path))
      parentMenuFunction(menuName, helpAction)
      global _helpActions
      _helpActions[menuName] = helpAction
docs: Adds a help menu to the plugin menu.
      This method should be called from the initGui() method of the plugin
  
      :param menuName: The name of the plugin menu in which the about menu is to be added.