>>> from punt3D import Punt3D

--ini-enunciat-punt
>>> p = Punt3D(0, 0, 0)
>>> print(str(p))
(0.0, 0.0, 0.0)

--fi-enunciat-punt
>>> from esfera import Esfera

--ini-enunciat-esfera
>>> c = Esfera(p, 1.0)
>>> print(str(c))
Esfera de centre (0.0, 0.0, 0.0) i radi 1.0
>>> print('{:.2f}'.format(c.volum()))
4.19

--fi-enunciat-esfera
>>> c = Esfera(p, 2.0)
>>> print(str(c))
Esfera de centre (0.0, 0.0, 0.0) i radi 2.0
>>> print('{:.2f}'.format(c.volum()))
33.51