This is indeed correct. Object references themselves in Java/Python are passed by value, which is why the following two code samples do not have the same effect

This is indeed correct. Object references themselves in Java/Python are passed by value, which is why the following two code samples do not have the same effect: Python 3.8.10 (default, Jun 22 2022, 20:18:18) [GCC 9.4.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> def f(d): ... d['foo'] 'bar'} ... >>> a = {} >>> f(a) >>> a {'foo': 'bar'} Python 3.8.10 (default, Jun 22 2022, 20:18:18) [GCC 9.4.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> def f(d): ... d = {'foo': 'bar'} ... >>> a = {} >>> f(a) >>> a {}