Given:

If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below 1000.

My Solution:

def sum_multiples(num, limit):
    """ Calculates the sum of multiples of a given number.
    Args:
        num: The multiple.
        limit: The upper limit.
    Returns:
        The sum of the terms of a given multiple.
    """
    sum = 0
    for i in xrange(num, limit, num):
        sum += i
    return sum
    
def sum(limit):
    return (sum_multiples(3, limit) +
            sum_multiples(5, limit) -
            sum_multiples(15, limit))
    
print sum(1000)

Is there any better or more pythonic way? I have used generators to for a very large calculation. Also, how can I get the running time for a given N?

Given:

If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below 1000.

My Solution:

def sum_multiples(num, limit):
    """ Calculates the sum of multiples of a given number.
    Args:
        num: The multiple.
        limit: The upper limit.
    Returns:
        The sum of the terms of a given multiple.
    """
    sum = 0
    for i in xrange(num, limit, num):
        sum += i
    return sum
    
def sum(limit):
    return (sum_multiples(3, limit) +
            sum_multiples(5, limit) -
            sum_multiples(15, limit))
    
print sum(1000)

Is there any better or more pythonic way? I have used generators for a very large calculation. Also, how can I get the running time for a given N?