>>> from notes import millor_pitjor_nota

>>> l = [['44444444D',8.3],['11111111A',7.25],['88888888H',4.1],['22222222B',3.8],['66666666F',5.3]] 
>>> m, p = millor_pitjor_nota(l)
>>> round(m, 2)
8.3
>>> round(p, 2)
3.8
>>> l = [['3A', 5]]
>>> m, p = millor_pitjor_nota(l)
>>> round(m, 2)
5
>>> round(p, 2)
5
>>> l = [['1A', 2], ['2B', 1], ['3C', 4]]
>>> m, p = millor_pitjor_nota(l)
>>> round(m, 2)
4
>>> round(p, 2)
1