Hmm, the resolution could be simple. But how about

>>> d = dict.fromkeys(range(100))
>>> for k in range(98):
...     del d[k]
... 
>>> it = iter(d)
>>> next(it)
98
>>> d.clear()
>>> d[0] = 1
>>> d[1] = 2
>>> next(it)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
StopIteration

Actually we haven't exhaust the dict yet. Is it reasonable for me to expect the second next returning 0? I actually mean is it reasonable for me to expect len(dict) elements returned before StopIteration raised even if the dict is changed?