Consider the code from the last assignment:
def prime_factors(n):
prime_factors = []
while n % 2 == 0:
n /= 2
prime_factors.append(2)
for i in range(3, int(math.sqrt(n)) + 1, 2):
while n % i == 0:
n /= i
prime_factors.append(i)
if n > 2:
prime_factors.append(int(n))
return prime_factors