>>> from estudiants import llistat

>>> dic = {('Pol','Amer','Coll'):['FI','CA','QM'],
... ('Aina','Soler','Gil'):['FI','CA','QM','ME'],
... ('Joan','Rubio','Boix'):['CA','QM','ME', 'AL'],
... ('Mar','Pou','Coll'):['CA','GE']}
>>> llistat(dic, 'FI')
['Amer Coll, Pol', 'Soler Gil, Aina']
>>> llistat(dic, 'PR')
[]