Set shortcut with DzActionMgr::addCustomAction?

I am unable to set a shortcut with DzActionMgr::addCustomAction. Can someone confirm it does not work, and I am not just doing something incorrectly?

I just posted a script in the thread Selecting the Active Viewport script or hotkey.

I was trying

MainWindow.getActionMgr().addCustomAction ('Action Text', 'Action Description', '{...}', false, 'Alt+1');

but no shortcut was set. I ended up calling DzActionMgr::setCustomActionShortcut to set the shortcut after creating the action instead.