def _not_divisible(n): return lambda x: x % n > 0

如下代码中如何理解：传入的实际参数，替换def中的x还是n？

def _not_divisible(n):
    return lambda x: x % n > 0

def _odd_iter():
    n = 1
    while True:
        n = n + 2
 yield n


def _not_divisible(n):
 return lambda x: x % n > 0


def primes(n):
 return lambda x: x % n > 0


def primes():
 yield 2
 it = _odd_iter()
 while True:
 n = next(it)
 yield n
 it = filter(_not_divisible(n), it)


for n in primes():
 if n < 1000:
 print(n)
 else:
 break