>>> from estudiantat import Assignatura

--ini-enunciat-
>>> a = Assignatura('240675', 4.5)
>>> a.ncredits
4.5
>>> a.codi
'240675'
>>> str(a)
'Assignatura 240675 4.5 crèdits'

--fi-enunciat-%
>>> b = Assignatura('240777', 9)
>>> b.ncredits
9
>>> b.codi
'240777'
>>> str(b)
'Assignatura 240777 9.0 crèdits'
>>> c = Assignatura('240666', 2.5)
>>> c.ncredits
2.5
>>> c.codi
'240666'
>>> str(c)
'Assignatura 240666 2.5 crèdits'