Chih Ying Yen xavierforge

## potter_kata.rs
#[derive(Default)]
pub struct ShoppingCart {
    counts: [usize; 5],
}

impl ShoppingCart {
    const BASE_PRICE: f64 = 100.0;

    pub fn new() -> Self {
        Self { counts: [0; 5] }
	#[derive(Default)]
	pub struct ShoppingCart {
	counts: [usize; 5],
	}

	impl ShoppingCart {
	const BASE_PRICE: f64 = 100.0;

	pub fn new() -> Self {
	Self { counts: [0; 5] }