pub fn add_item(&mut self, amount: Amount, product: P) {
        let item = BillItem { amount, product };

        self.add(item)
    }
/// Instantiates and adds a new `BillItem` to the list.
Instantiates and adds a new `BillItem` to the list.
Instantiates and adds a new ` BillItem ` to the list .
pub fn add_item(&mut self, amount: Amount, product: P) {
        let item = BillItem { amount, product };
        self.add(item)
    }
pub fn add_item ( & mut self , amount : Amount , product : P ) { let item = BillItem { amount , product } ; self . add ( item ) }
Instantiates and adds a new `BillItem` to the list.
Instantiates and adds a new ` BillItem ` to the list .
&mut self
amount
Amount
product
P
&mut self
amount
Amount
product
P