Question

Im having some trouble understanding Inheritance in classes and wondering why this bit of python code is not working, can anyone walk me through what is going wrong here?

## Animal is-a object 
class Animal(object):
    def __init__(self, name, sound):
        self.implimented = False
        self.name = name
        self.sound = sound

    def speak(self):
        if self.implimented == True:
            print "Sound: ", self.sound

    def animal_name(self):
        if self.implimented == True:
            print "Name: ", self.name



## Dog is-a Animal
class Dog(Animal):

    def __init__(self):
        self.implimented = True
        name = "Dog"
        sound = "Woof"

mark = Dog(Animal)

mark.animal_name()
mark.speak()

This is the output through the terminal

Traceback (most recent call last):
  File "/private/var/folders/nd/4r8kqczj19j1yk8n59f1pmp80000gn/T/Cleanup At Startup/ex41-376235301.968.py", line 26, in <module>
    mark = Dog(Animal)
TypeError: __init__() takes exactly 1 argument (2 given)
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I was trying to get animal to check if an animal was implemented, and then if so, get the classes inheriting from animal to set the variables that Animals would then be able to manipulate.

Answer 1

1. To create an instance of a class you do

   mark = Dog()
   

   not mark = Dog(Animal).

2. Don’t do this implimented stuff. If you want a class that you can’t instantiate (i.e. you have to subclass first), do

   import abc
   class Animal(object):
       __metaclass__ = abc.ABCMeta
   
       def speak(self):
           ...