What are mutable class variables in Python?

Can you explain what mutable class variables are in Python?

Sure! Mutable class variables are variables that can be changed after their creation. They are shared across all instances of a class.

Can you give me an example of mutable class variables?

Absolutely! Here's a simple example:

class MyClass:
    shared_list = []  # mutable class variable

    def add_item(self, item):
        MyClass.shared_list.append(item)

obj1 = MyClass()
obj1.add_item('apple')

obj2 = MyClass()
obj2.add_item('banana')

print(MyClass.shared_list)  # Output: ['apple', 'banana']

What happens if I change the mutable class variable in one instance?

If you change the mutable class variable in one instance, the change will reflect in all instances since they share the same variable.

Are there any best practices for using mutable class variables?

Yes, it's generally a good practice to avoid using mutable class variables for storing state that is specific to an instance. Instead, use instance variables.