>>> from afinitats import maxima_val

>>> r = maxima_val([('id2',4), ('id3',7), ('id4',5), ('id7',9)])
>>> r
('id7', 9)
>>> r = maxima_val([('id1',6), ('id3',2), ('id5',8)])
>>> r
('id5', 8)
>>> r = maxima_val([('id1',5), ('id2',8)])
>>> r
('id2', 8)
>>> r = maxima_val([('id1',8), ('id5',7), ('id6',4)])
>>> r
('id1', 8)