'Initializes the textbooks in the course and adds the given number of books to each textbook'

def set_up_books(self, num_books):

    self.books = [MagicMock() for _ in range(num_books)]
    for (book_index, book) in enumerate(self.books):
        book.title = 'Book{0}'.format(book_index)
    self.course.textbooks = self.books
    self.course.pdf_textbooks = self.books
    self.course.html_textbooks = self.books
