# Итераторы
class MyRangeIterator:
    def __init__(self, top):
        self.top = top
        self.current = 0
        
    def __iter__(self):
        return self
    
    def __next__(self):
        if self.current >= self.top:
            raise StopIteration
            
        current = self.current
        self.current += 1
        
        return current
    
counter = MyRangeIterator(3)
for it in counter:
    print(it)