Some people may consider:

    def is_prime(n):
        if n % 2 == 0:
            return False

        sqrt_n = int(math.floor(math.sqrt(n)))
        for i in range(3, sqrt_n + 1, 2):
            if n % i == 0:
                return False
        return True

    def main():
        with concurrent.futures.ProcessPoolExecutor() as executor:
            for number, prime in zip(PRIMES, executor.map(is_prime, PRIMES)):
                print('%d is prime: %s' % (number, prime))

uglier than (borrowing some JavaScript syntax):

    def main():
        with concurrent.futures.ProcessPoolExecutor() as executor:
            for number, prime in zip(PRIMES, executor.map(
                    function(n) {
                        if n % 2 == 0:
                            return False

                        sqrt_n = int(math.floor(math.sqrt(n)))
                        for i in range(3, sqrt_n + 1, 2):
                            if n % i == 0:
                                return False
                        return True
                    }
                    , PRIMES)):

                print('%d is prime: %s' % (number, prime))

I don't, mostly because in the second example, I cannot unit test the anon version of is_prime in isolation. This is a rather trivial case, but I've seen much more complex and enigmatic anon functions in Node applications.

Note: the original comes from http://docs.python.org/dev/library/concurrent.futures.html#p...