input: Write a python function to sum all the multiples of 3 or 5 below a given number.
  assert sumMultiples(10) == 23
  assert sumMultiples(20) == 78
  assert sumMultiples(50) == 543
output: def sumMultiples(n):
      return sum(x for x in range(n) if x % 3 == 0 or x % 5 == 0)