What is the equivalent of NotImplementedError using Python

Question

Hi all. So basically I use Python 2.x 

And here, whenever we want to use a method which is abstract we define it as follows:

class Base:
    def foo(self):
        raise NotImplementedError("Subclasses should implement this!")

And later, let us say I forgot to override it. This is where I get the exception, right? 

IS there any nice way to consider a field to be marked as abstract? Or can it be done easily by changing and adding in the documentation string and considering that solves the issue?

All help appreciated, cheers!

Answer 1

Hi, good question!

One simple answer to your question is YES! You can make use of the @property decorator just for this purpose.

Consider this instance - Let us say you have a field called "example", then is almost not possible to do this:

class Base(object):

    @property
    def example(self):
        raise NotImplementedError("Implement using Subclasses!")

And basically running the below code gives you a NotImplementedError exactly as expected!

c = Base()
print c.example