[4pt] Implement methods

[AyoMoses1]

Implement methods:

• add_item method in the Genre class

  • [ ] should take an instance of the Item class as an input
  • [ ] should add the input item to the collection of items
  • [ ] should add self as a property of the item object (by using the correct setter from the item object)

• can_be_archived?() in the MusicAlbum class

  • [ ] should override the method from the parent class
  • [ ] should return true if parent's method returns true AND if on_spotify equals true
  • [ ] otherwise, it should return false