Method pop

crates/vm/src/builtins/set.rs:345–353

(&self, vm: &VirtualMachine)

    }

    fn pop(&self, vm: &VirtualMachine) -> PyResult {
        // TODO: should be pop_front, but that requires rearranging every index
        if let Some((key, _)) = self.content.pop_back() {
            Ok(key)
        } else {
            let err_msg = vm.ctx.new_str(ascii!("pop from an empty set")).into();
            Err(vm.new_key_error(err_msg))
        }
    }

    fn update(
        &self,