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

Answer 1

My simple solution which is based on the default value of function parameters.

def getSystemContext(contextObjList=[]):
    if len( contextObjList ) == 0:
        contextObjList.append( Context() )
        pass
    return contextObjList[0]

class Context(object):
    # Anything you want here