You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: remove.rs
    path of file: ./repos/Relm4/relm4/src/extensions
    
    the code of the file until where you have to start completion: use crate::{ContainerChild, RelmSetChildExt};
use gtk::prelude::*;

/// Widget types which can have widgets removed from them.
pub trait RelmRemoveEx
    
    fn remove_all(&self) {
        use adw::traits::ExpanderRowExt;

        while let Some(child) = self.last_child() {
            let row = child
                .downcast::<gtk::ListBoxRow>()
                .expect("The child of `ExpanderRow` is not a `ListBoxRow`.");
            row.set_child(None::<&gtk::Widget>);
            self.remove(&row);
        }
    }