| t | class Pushpull: | t | class Pushpull: | 
             |  |  |  | 
             |     def __init__(self, n=0): |  |     def __init__(self, n=0): | 
             |         Pushpull.pos = n |  |         Pushpull.pos = n | 
             |  |  |  | 
             |     def push(self, n=1): |  |     def push(self, n=1): | 
             |         Pushpull.pos += n |  |         Pushpull.pos += n | 
             |  |  |  | 
             |     def pull(self, n=1): |  |     def pull(self, n=1): | 
             |         Pushpull.pos -= n |  |         Pushpull.pos -= n | 
             |  |  |  | 
             |     def __iter__(self): |  |     def __iter__(self): | 
             |         if Pushpull.pos < 0: |  |         if Pushpull.pos < 0: | 
             |             return iter(range(0, Pushpull.pos, -1)) |  |             return iter(range(0, Pushpull.pos, -1)) | 
             |         else: |  |         else: | 
             |             return iter(range(Pushpull.pos)) |  |             return iter(range(Pushpull.pos)) | 
             |  |  |  | 
             |     def __str__(self): |  |     def __str__(self): | 
             |         if Pushpull.pos < 0: |  |         if Pushpull.pos < 0: | 
             |             return f'<{abs(Pushpull.pos)}<' |  |             return f'<{abs(Pushpull.pos)}<' | 
             |         elif Pushpull.pos > 0: |  |         elif Pushpull.pos > 0: | 
             |             return f'>{Pushpull.pos}>' |  |             return f'>{Pushpull.pos}>' | 
             |         else: |  |         else: | 
             |             return '<0>' |  |             return '<0>' |