prime generator in python

prime.py

def nats(n):
    while True:
        yield n
        n += 1


# another nats implementation
def nats2(n):
    yield n
    yield from nats2(n+1)


def sieve(stream):
    n = next(stream)
    yield n
    yield from sieve(i for i in stream if i % n != 0)
    

def primes()
    return sieve(nats(2))