new_contents: def multiples_of_3_and_5(num=1000):
      for i in range(num):
          if i % 3 == 0 or i % 5 == 0:
              yield i
  
  if __name__ == '__main__':
      print(sum(multiples_of_3_and_5()))
  
subject: complete 1 multiples of 3 and 5