Milliseconds in python?

[Matt O'leary]

Me and my friend were testing our python skills by writing a simple code that calculates prime numbers. It also shows how long it took and how many calculations it did.

Here is the src:

import time
calc = 0
def calculate(max):
global calc
for a in range(1,max):
for b in range(1,max):
calc = calc + 1
if a*b == max:
return False
return True
max = int(input('Enter max number: '))
for i in range(1,max):
sec = time.time()
if calculate(i):
print('I found the prime number {} in {}! It took {} calculations to find!'.format(i, time.strftime('%H:%M:%S',time.gmtime(time.time()-sec)), calc))


This outputs: I found the prime number x in 00:00:00! It took x calculations to find!

What we want to add are the milliseconds behind 00:00:00. Does anyone know how? 

Any help is appreciated!

Matt Jeevus