from esfera import Esfera


class Pilota(Esfera):
    def __init__(self, radi, centre, pes, color):
        super().__init__(centre, radi)
        self.pes = pes
        self.color = color

    def __str__(self):
        s = super().__str__()
        return s.replace("Esfera", "Pilota")

    def densitat(self):
        return self.pes / self.volum()