Find all Prime Numbers in Range (Python)

import math

def checkNumPrime(n):
        ''' Check whether n is a prime number
        '''

        # Numbers less than 4 are all prime
        if n < 4:
                return True

        # Numbers divisible by 2 or 3 aren't prime
        if n%2 == 0 or n%3 == 0:
                return False

        # Create the seeds
        di=2
        i=5

        # Work out the square root of n 
        # (no need to check anything higher)
        lim = math.floor(math.sqrt(n))

        while i < lim:
                if n%i == 0:
                        return False

                i=i+di
                di=6-di

        # If we got this far, didn't find a whole number.
        # Number is prime
        return True

def calculatePrimesForRange(s,e):
        ''' Iterate over each integer between start and end

            return list
        '''
        primes = []
        while s < e:
                if checkNumPrime(s):
                        primes.append(s)
                s = s+1

        return primes