how.puml

@startuml
'https://plantuml.com/class-diagram

package "Domain" #DDDDDD {

    class Client {
        - Wallet $wallet
        .. Getters ..
        + getWallet(): Wallet
        .. Business logic ..
        + subtractMoney(float $amount): void
    }

    class Wallet {
        - float $money
        .. Business logic ..
        + subtractMoney(float $amount): void
    }

    class Order {
        - Item[] $items
        .. Business logic ..
        + calculateAmount(): float
    }

    class Item {
        - float $price
        .. Getters ..
        + getPrice(): float
    }

    class OrderService {
        - Client $client
        - Order $order
        .. Business logic ..
        + makeOrder(): void
    }

    Client::$wallet o-- Wallet
    Order::$items o-- Item
    OrderService::$order ..> Order
    OrderService::$client ..> Client
}

@enduml