To test for primality, we confected a brute-force procedure. It goes like this.

1. check if 2|n. If it does, return False.
2. check if 3|n. If it does, return False.
3. check if 4|n. If it does, return False.
4. Keep going until we get to n - 1
5. If False is never returned, return True.

def is_prime_brute(n):
    for k in range(2, n):
        if n%k == 0:
            return False
    return True
print(is_prime(61))
print(is_prime(997))
print(is_prime(1000000007))