Error calling ElementaryParticle(spin).hear_me()

[ostueker]

Cell [29] in notebook ch06-classes-objects.ipynb gives an error as the (overloaded) constructor of the ElementaryParticle class doesn't create the data attributes initialized bu the generator of the Particle class.

This can be solved by calling Particle.__init__(self) explicitly:

# elementary.py
class ElementaryParticle(Particle):

    roar = "I am an Elementary Particle!"

    def __init__(self, spin):
        Particle.__init__(self)
        self.s = spin
        self.is_fermion = bool(spin % 1.0)
        self.is_boson = not self.is_fermion