>>> from extraccio import extreu_negatius

--ini-enunciat

>>> it = iter('Avui estarem entre -10 i -5 graus centígrads'.split())
>>> itr = extreu_negatius(it)
>>> next(itr)
-10
>>> next(itr)
-5
>>> next(itr, 'final')
'final'

>>> for num in extreu_negatius(iter('-5  89 i -123 són nombres enters però -12.345 no ho és'.split())):
...    print(num*2)
-10
-246

--fi-enunciat

>>> for num in extreu_negatius(iter('Operacions: -2 x -4 = 8 ;; 50 x -2  = -100 ;;  -12 x -11 = ??'.split())):
...    print(num, end=',')
-2,-4,-2,-100,-12,-11,

>>> for num in extreu_negatius(iter('-1 -2 A17 B-28 -100 +45 -200 15-02-2025 -90 5678 -123245'.split())):
...    print(num, end=',')
-1,-2,-100,-200,-90,-123245,