실행하면 원하는 숫자들은 나오는데 None가 같이 출력되요.,. 어떻게 해야 none가 사라질까요?

class Multi_Iterator:
    def __init__(self, multi, stop):
        self.multi = multi
        self.stop = stop
        self.current = 0

    def __iter__(self):
        return self
    def __next__(self):
        self.current += 1
        if self.current > self.stop:
            raise StopIteration
        elif ((self.current%self.multi) == 0):
            return self.current



for i in Multi_Iterator(2, 10):
    print(i, end=' ')
print('\n')
for i in Multi_Iterator(3, 20):
    print(i, end=' ')
print('\n')
for i in Multi_Iterator(5, 30):
    print(i, end=' ')