prime numbers generator

primes.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from itertools import count, takewhile, islice

def primes():
    yield 2
    yield 3
    primes = [2, 3]
    for i in count(start=5, step=6):
        for n in (i, i + 2):
            limit = n**0.5 + 1
            trial = takewhile(lambda x: x < limit, primes)
            if all(n % prime != 0 for prime in trial):
                yield n
                primes.append(n)

# prime numbers less than 30
print list(takewhile(lambda x: x<30, primes()))
# 10 prime numbers
print list(islice(primes(), 10))