>>> from preus import incrementa_preus

--ini-enunciat
>>> inc = iter([1, 3, 1, 2])
>>> it = incrementa_preus(4, inc)
>>> for i in it:
...    print(i, end = ',')
5,8,9,11,
>>> next(it, 'final')
'final'

--fi-enunciat

>>> inc1 = iter([-1, 2, 4, -1, 3])
>>> it1 = incrementa_preus(28, inc1)
>>> next(it1)
27
>>> next(it1)
29
>>> for i in range(3):
...    next(it1)
33
32
35
>>> next(it1, 'final')
'final'

>>> inc2 = iter([1, 1, 2, 2, -1, -2, 3, 3])
>>> it2 = incrementa_preus(55, inc2)
>>> next(it2)
56
>>> next(it2)
57
>>> for i in range(5):
...     a = next(it2)
>>> next(it2)
64
>>> next(it1, 'final')
'final'

>>> inc3 = iter([10, -8, 11, 12, -10, 14, 7, 8])
>>> it3 = incrementa_preus(150, inc3)
>>> for i in it3:
...    i
160
152
163
175
165
179
186
194
>>> next(it1, 'final')
'final'