# В тюпл (tuple)
def fun(param):
    if param:
        return ('foo' , 'bar', 'one', 'two')
    else:
        return (None, None, None, None)
# В лист
def fun(param):
    if param:
        return ['foo' , 'bar', 'one', 'two']
    else:
        return [None, None, None, None]