pub fn clean(&mut self) {
        for category in &mut self.categories {
            category.clean();
        }
    }
/// Cleans the [TaskList], removing all completed tasks.
Cleans the [TaskList], removing all completed tasks.
Cleans the [ TaskList ] removing all completed tasks .
pub fn clean(&mut self) {
        for category in &mut self.categories {
            category.clean();
        }
    }
pub fn clean ( & mut self ) { for category in & mut self . categories { category . clean ( ) ; } }
Cleans the [TaskList], removing all completed tasks.
Cleans the [ TaskList ] removing all completed tasks .
&mut self
&mut self