>>> from notes import perc_aprovats   

>>> l = [['44444444D',8.3],['11111111A',7.25],['88888888H',4.1],['22222222B',3.8],['66666666F',5.3]]
>>> round(perc_aprovats(l), 2)
0.6
>>> l = [['3A', 5]]
>>> round(perc_aprovats(l), 2)
1.0
>>> l = [['1A', 2], ['2B', 1], ['3C', 4]]
>>> round(perc_aprovats(l), 2)
0.0