from dataclasses import dataclass
from typing import List

@dataclass
class Book:
    """Represents a book with title and author"""
    title: str
    author: str

class Library:
    """Represents a library with a collection of books"""
    def __init__(self):
        self.books: List[Book] = []

    def add_book(self, book: Book):
        """Adds a book to the library"""
        self.books.append(book)

    def list_books(self):
        """Lists all books in the library"""
        for book in self.books:
            print(f"Title: {book.title}, Author: {book.author}")

def main():
    """Main entry point of the application"""
    library = Library()

    book1 = Book("To Kill a Mockingbird", "Harper Lee")
    book2 = Book("1984", "George Orwell")

    library.add_book(book1)
    library.add_book(book2)

    library.list_books()

if __name__ == "__main__":
    main()