>>> import itertools
>>> from sumesp import sumes_parcials

--ini-enunciat

>>> it1 = iter(range(100))
>>> it2 = iter([2, 5, 1, 2, 6])
>>> itsum = sumes_parcials(it1, it2)
>>> next(itsum)  # 0+1 
1
>>> next(itsum)  # 2+3+4+5+6 
20
>>> next(itsum)  # 7
7
>>> next(itsum)  # 8+9
17
>>> next(itsum)  # 10+11+12+13+14+15
75
>>> next(itsum, 'final')
'final'

--fi-enunciat

>>> l1 = [1,-6,77,8,99,19,-22,67,-12,55,89,9,0,11,-2]
>>> l2 = [3,1,4,7]
>>> for x in sumes_parcials(iter(l1), iter(l2)):
...     print(x, end=',')
72,8,163,150,
>>> for x in sumes_parcials(iter(l1), iter([1,2]*5)):
...     print(x, end=',')
1,71,8,118,-22,55,55,98,0,9,
>>> for x in sumes_parcials(itertools.count(), iter([1000]*10)):
...     print(x, end=',')
499500,1499500,2499500,3499500,4499500,5499500,6499500,7499500,8499500,9499500,