classes.py

class LivingBeing(object):
    breathes = True
    needs_water = True

    def cease_living():
        pass


class Plant(LivingBeing):
    has_eyes = False
    has_legs = False

    def eats():
        pass


class Animal(LivingBeing):
    has_eyes = True
    has_legs = True

    def eats():
        pass

    def sleeps():
        pass

    def moves():
        pass