PythonAPI, Python script can access the default Unreal editor's Menus but cannot get the customized menu bar.

Hi, first time posting question here and let me know if I post to a wrong place. Thanks in advance.

In our development team, we added a customized menu called “ABC” by C++.

And then some of developers want to add cutsomized submenus through python. So we need to first get the ABC menu using python. But the python only work Unreal engine default menus , such as

toolMenus = unreal.ToolMenus.get()                          
fileMenu  = toolMenus.find_menu("MainFrame.MainMenu.File") 
print(fileMenu)
LogPython: <Object '/Engine/Transient.ToolMenus_0:RegisteredMenu_113' (0x0000063F35626B80) Class 'ToolMenu'>

but when we want to access the ABC menu using similar way, it return None.

toolMenus = unreal.ToolMenus.get()                          
fileMenu  = toolMenus.find_menu("MainFrame.MainMenu.ABC") 
print(fileMenu)
LogPython: None

How to let the python API be able to access the C++ added cutstomized new menu ? Do we need to rebuild the pythonAPI and modify some part of the code to let include the new menu in pythonAPI ? Any tip or help is super appreciated.