How to Fix: TypeError: method takes 1 positional argument but 2 were given
You called my_object.method(x) and passed one argument. Python counted two. The second argument is the instance itself — Python injected it automatically, and your method…
Django Permissions: How to Use UserPassesTestMixin (Beyond Login)
In our last security guide, we used LoginRequiredMixin to block logged-out users. But this still leaves a security hole: Any logged-in user can edit any…
How to Fix: NotImplementedError in Python (OOP Guide)
This error looks scary, but it’s actually a helpful message from a developer. In Python, the NotImplementedError is not a bug; it’s a feature of…
Python Dunder Methods: What __init__ and __str__ Really Mean
“Dunder” is short for “Double Underscore.” Dunder methods are special “magic” methods that Python reserves for its own use. You don’t call them directly, but…
Inheritance in Python: How to Re-use Code in Classes
In our Guide to OOP, we created a Dog class. But what if we also need a Cat class? They both have names and ages….
Object-Oriented Programming (OOP) in Python: A Beginner’s Guide to Classes and Objects
You’ve learned functions, loops, and variables. You can write scripts. But to build large applications (like with Django), you need a better way to organise…
