> Cascading methods: that's a big no. The idiom is that if a method may change the state of the object then it should return None (eg `set.add`) So methods tha

> Cascading methods: that's a big no. The idiom is that if a method may change the state of the object then it should return None (eg `set.add`) So methods that mutate state, and don't return None are un-Pythonic? What about this example: a = [1, 2, 3] b = a.pop() pop() mutates the state of a and returns a value that is not None. Is the Python code language itself un-Pythonic?