Depends on what you mean by "technically". Computationally, python lambda is fully capable of whatever a regular python function can do, including side-effects

Depends on what you mean by "technically". Computationally, python lambda is fully capable of whatever a regular python function can do, including side-effects, (you can call foo.set_bar()). The limit is syntactical: a lambda has to be one single expression. So, no assignment statement, no multiple lines, etc.