def is_prime(n):
    """
    Return a boolean value based upon
    whether the argument n is a prime number.
    """
    if n < 2:
        return False
    if n == 2:
        return True
    for m in range(2, int(n ** 0.5) + 1):
        if (n % m) == 0:
            return False
    else:
        return True