def METHOD_NAME(self):
    """Gets the ID for the next modifier in the UI"""
    # This is NOT a property, otherwise the modifiers property would access this...
    # Which acesses the modifiers property... INFINITE RECURSION! :D
    ids = [mod.display_order for mod in self.modifiers]
    if ids:
        return max(ids) + 1
    else:
        return 0