[3pt] Implement methods:

[beteland123]

Implement methods:
add_item method in the Label 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 Book class
should override the method from the parent class
should return true if parent's method returns true OR if cover_state equals to "bad"
otherwise, it should return false