How to update an object's method in python

Question

Say I have a class and an object of it.

In Python, you can update the behavior of an object's method by re-assigning the method to a new function. This is possible because methods in Python are just attributes of an object that happen to be functions. Here's an example of how you can do this:

class MyClass:
    def my_method(self):
        print("Original behavior")

# create an instance of the class
obj = MyClass()

# call the original method
obj.my_method()  # Original behavior

and I want to update its method:

# update the method with a new function
def new_behavior(self):
    print("New behavior")

obj.my_method = new_behavior

# call the updated method
obj.my_method()  # New behavior

This gives me an error:

TypeError: new_behavior() missing 1 required positional argument: 'self'

Is this the correct way to update an object's method? How should I do it?