Is there a simple, elegant way to define singletons? [duplicate]

Answer 1

I'm very unsure about this, but my project uses 'convention singletons' (not enforced singletons), that is, if I have a class called DataController, I define this in the same module:

_data_controller = None
def GetDataController():
    global _data_controller
    if _data_controller is None:
        _data_controller = DataController()
    return _data_controller

It is not elegant, since it's a full six lines. But all my singletons use this pattern, and it's at least very explicit (which is pythonic).