[SCALA]

Write a program with:

1. A class named "Battery" that:

- Has a constructor that takes a variable named "charge" of type Int

2. A class named Flashlight that:

- Has a constructor that takes no parameters

- When a new FlashLight is created, declare a state variable named "battery" of type Battery and set it to a new Battery with 5 charge (ie. Batteries included)

- A method named "use" that takes no parameters and returns Unit

--- This method(use) will decrease the charge of the FlashLight's battery by 1 - If the charge is 0, this method does nothing

- A method named "replaceBattery" that takes a Battery as a parameter and returns a Battery

--- This method(replaceBattery) swaps the input Battery with the Battery currently stored in this FlashLight's state variable

--- The returned Battery is the one that was in the state variable when the method is called