An example of setting up a notifier for command argument in MODO SDK. Snatched from post by James O'Hare on MODO slack coding channel.

ArgumentNotifier.py

class Notifier(lxifc.UIValueHints):
    def __init__(self):
        self._notifiers = [('channel.value', '+v channelName itemType'),]
     
    def uiv_NotifierCount(self):
        return len(self._notifiers)

    def uiv_NotifierByIndex(self, index):
        return self._notifiers[index] 

class MyCommand(lxu.command.BasicCommand):
    def arg_UIValueHints(self, index):
        if index == IndexForNotifier:
            return Notifier()