Example code - Inheritance issues

The challenges in inheritance can not be demonstrated well in a powerpoint. Thus, I made this page with examples. You can copy the code in the section and add it together and run it.

First I create a slightly bigger CatClass.

class CatClass:
    ### Class variables
    genus = "Felis"
    species = "Catus"
    acts = {'scratch': "purrs",
            'scare': "jumps high in the air",
            'feed': "is very excited" }

    ### Instatiation
    def __init__(self, name, gender):
        self.name, self.gender = name, gender

    ### Magic methods
    # Addition makes a kitten if male and female cat, alternative constructor
    def __add__(self, other):
        # Taken a short cut and just demanding the genders to be different to breed
        if self.gender == other.gender:
            return NotImplemented
        # Being biased and saying all kittens are male
        kitten = CatClass('Unnamed kitten', 'male')
        return kitten     
        
    ### Class methods
    # Adding a cat action
    @classmethod
    def add_action(cls, action, reaction):
       cls.acts[action] = reaction
    # Querying class for number of actions
    @classmethod
    def count_action(cls):
        return len(cls.acts)

    ### Property methods
    # age setter and getter
    @property
    def age(self):
        if not hasattr(self, '_age'):
            raise NameError("Age of cat is not yet set")
        return self._age
        
    @age.setter
    def age(self, value):
        if value < 0:
            raise ValueError("Age can not be negative")
        self._age = value

    ### Instance methods
    # The action method - using class variables
    def action(self, act):
        if act in CatClass.acts:
            print(self.name, CatClass.acts[act])
        elif self.gender == 'male':
            print(self.name, "looks bored")
        else:
            print(self.name, "yawns")

### Main program                    
yourcat = CatClass('Missy', 'female')
yourcat.age = 5
print(f"The age of your cat is {yourcat.age}")

CatClass.add_action("annoy", "scratches your face")
print("Actions in CatClass:", CatClass.count_action())

mycat = CatClass("Tom", "male")
kitten = mycat + yourcat

print(f"Kitten: {kitten.name}")

yourcat.action('scare')

This class looks fine, but it has a number of inheritance issues. By creating a Tiger class that inherits from the CatClass, I will demonstrate.

class Tiger(CatClass):
    acts = {
        'scratch': 'roars',
        'feed': 'demands more meat'
    }

tigger = Tiger("Shere Khan", "male")
tigger.action("scratch")
tigger.action('scare')