re-run-generator.py

>>> def gen():
...     yield from [1, 2, 3]
...
>>> g = gen()
>>> for i in g: print(i)
...
1
2
3
# generator exhausted:
>>> for i in g: print(i)
...

# reusable generator:
>>> class Gen:
...     def __iter__(self):
...             yield from [1, 2, 3]
...
>>> g = Gen()
>>> for i in g: print(i)
...
1
2
3

# now you can iterate again:
>>> for i in g: print(i)
...
1
2
3