No lambda

class fn:
    def __init__(gen):
        self.gen = gen
    def __call__(*args):
        fn.args = args
        return self.gen.next()

f = fn(a+b+c for a,b,c in fn.args)
f(2,3,4)        

f = lambda a,b,c: a+b+c
f(2,3,4)