class Library(object): """A collection of book objects."""

def __init__(self): self.books = []

def __repr__(self): return '' % (len(self.books))

def list_books(self): """List all the books in the library."""

if len(self.books) == 0: print "Library is empty." return for book in self.books: print book.title print ' Author:', book.author print ' Published:', book.pub_yr print

def add_book(self, book): """Add a book to the library."""

if not isinstance(book, Book): raise Exception('Please enter a Book Object to add to the library') self.books.append(book) print 'Added: %s' % (book.title)

def empty_library(self): """Remove all books from the library.""" pass

Question: Instantiate a library object