SelfAssignable

Observed

Correction

Here is what's right.

You cannot update an object by reassigning self. The first parameter of an instance method, conventionally named self, is a reference to the object on which the method is called. However, reassigning self does not change the instance itself, as it is just a reference variable to the object instance.

Reassigning self only changes what the local variable self points to within the method’s scope.

For example:

class C:
    def __init__(self):
        self = 42
        print(self)


obj = C()   # displays 42
print(obj)  # displays <__main__.C object at ...>

Symptoms

How do you know your students might have this misconception?

This misconception can manifest itself in code like the following:

class C:
    def __init__(self):
        self = C()

In this case, students may also be unaware of the fact that the expression C() will result in infinite recursion (and stack overflow).