Prime number Python homework

[DeaD_EyE]

Write a function, which checks a number, if it's a prime.
In another function you collect primes, until you have the number of primes you want to have.

from itertools import count


def is_prime(number):
    """Your implementation"""
    return True


def get_primes(n):
    primes = []
    while len(primes) < n:
        for number in count():
            if is_prime(number):
                primes.append(number)
    return primes

The function to check the prime can also taken from other libraries.
If you make the easiest implementation, it takes more time to check primes.