Find largest prime factor (optimal)

largest_prime_factor.py

def get_largest_prime_factor(number):
    prime_factors = []
    divisor = 1
    i = 1
    while(i <= number // divisor):  # integer division
        if number % i == 0:  # if number is divisible by i
            divisor = i  # found a divisor, is used in line 5 to "short" the stop clause
            if is_prime(divisor):  # filter only prime divisors (factors)
                prime_factors.append(divisor)
        i += 1
    return prime_factors[-1]  # get latest item in prime_factors list