fn new() -> Self {
        Self {
            inner: HashMap::new(),
        }
    }
/// Create a new bills collection.
Create a new bills collection.
Create a new bills collection .
fn new() -> Self {
        Self {
            inner: HashMap::new(),
        }
    }
fn new ( ) -> Self { Self { inner : HashMap :: new ( ) , } }
Create a new bills collection.
Create a new bills collection .