1. **Constants and Drink Recipes:**
- **WATER_UNIT, MILK_UNIT, BEANS_UNIT:** These constants represent the basic amounts of water, milk, and coffee beans required to make one drink.
- **DRINKS Dictionary:** This contains the recipe for each type of drink (espresso, latte, cappuccino), including the price and the required amounts of water, milk, and beans.
2. **State Variables:**
- **total_water, total_milk, total_beans, total_cups, total_money:** These variables keep track of the machine's current resources and money.
3. **Functions:**
- **`display_machine_status()`:** Prints the current status of the machine, showing the available water, milk, beans, cups, and money.
- **`can_make_drink(drink)`:** Checks if the machine has enough resources (water, milk, beans) to make the selected drink.
- **`make_drink(drink)`:** Deducts the required resources from the machine and adds the drink's price to the total money.
- **`buy_drink()`:** Prompts the user to select a drink, checks if it can be made, and processes the transaction if possible.
- **`fill_machine()`:** Allows the user to add water, milk, beans, and cups to the machine.
- **`take_money()`:** Empties the machine's money into the user's account.
- **`main_menu()`:** The main loop of the program, where users can choose to buy a drink, fill the machine, take money, display the machine's status, or quit the program.
4. **Main Program:**
- The `main_menu()` function is called when the program starts, providing a simple text-based interface for interacting with the coffee machine.
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### **Key Concepts:**
- **Resource Management:** The code keeps track of limited resources (water, milk, beans, cups) and updates them as drinks are made or the machine is refilled.
- **User Interaction:** The user can interact with the machine through a series of text inputs, making it a simple simulation of a real coffee machine.
- **Condition Checking:** The program checks whether there are enough resources before making a drink, ensuring that operations are realistic.
This code provides a clear example of how to manage state and handle user inputs in a simple simulation. It effectively models a coffee machine’s operations, from purchasing drinks to refilling supplies and managing funds.