def is_prime(number: int) -> bool:

    # precondition
    assert isinstance(number, int) and (
        number >= 0
    ), "'number' must been an int and positive"

    status = True

    # 0 and 1 are none primes.
    if number <= 1:
        status = False

    for divisor in range(2, int(round(sqrt(number))) + 1):
        # if 'number' divisible by 'divisor' then sets 'status'
        # of false and break up the loop.
        if number % divisor == 0:
            status = False
            break

    # precondition
    assert isinstance(status, bool), "'status' must been from type bool"

    return status