>>> from taulers import TaulerSE
>>> from iserps import iter_serps

>>> t = TaulerSE(63)
>>> t.afegir_escala(3, 17)
>>> t.afegir_serp(11, 25)
>>> t.afegir_escala(28, 42)
>>> t.afegir_serp(16, 32)
>>> t.afegir_serp(34, 48)
>>> t.afegir_escala(40, 46)
>>> t.afegir_serp(45, 58)

>>> it = iter_serps(t)
>>> for tup in it:
...     print(tup)
(25, 11)
(32, 16)
(48, 34)
(58, 45)
>>> next(it, 'final')
'final'