class_start.py

# Python Object Oriented Programming by Joe Marini course example
# Using class-level and static methods


class Book:
    # TODO: Properties defined at the class level are shared by all instances
    BOOK_TYPES = ("HARDCOVER","PAPERBACK","EBOOK")

    # TODO: double-underscore properties are hidden from other classes
    __booklist = None

    # TODO: create a class method
    @classmethod
    def get_book_types(cls):
        return cls.BOOK_TYPES

    # TODO: create a static method
    def getbooklist():
        if Book.__booklist == None:
            Book.__booklist = []
        return Book.__booklist

    # instance methods receive a specific object instance as an argument
    # and operate on data specific to that object instance
    def set_title(self, newtitle):
        self.title = newtitle

    def __init__(self, title, booktype):
        self.title = title
        if (not booktype in Book.BOOK_TYPES):
            raise ValueError(f"{booktype} is not a valid book type!")
        else:
            self.booktype = booktype

    # def __repr__(self):
    #     return f"Book(title={self.title})"

# TODO: access the class attribute
print("Book Types: ", Book.get_book_types())

# TODO: Create some book instances
b1 = (Book("Title1", "HARDCOVER"))
b2 = (Book("Title2", "PAPERBACK"))
# print(b1.title)
# print(b1.booktype)

# TODO: Use the static method to access a singleton object
thebooks = Book.getbooklist()
thebooks.append(b1)
thebooks.append(b2)
print(thebooks)