'Create multiple entries for books with multiple authors
Given a list of books by author, scan list for books with multiple
authors. Add a cloned copy of the book per additional author.
Args:
books_by_author (list): book list possibly containing books
with multiple authors
Return:
(list): books_by_author with additional cloned entries for books with
multiple authors'

def relist_multiple_authors(self, books_by_author):

    multiple_author_books = []
    for book in books_by_author:
        if (len(book['authors']) > 1):
            multiple_author_books.append(book)
    for book in multiple_author_books:
        cloned_authors = list(book['authors'])
        for (x, author) in enumerate(book['authors']):
            if x:
                first_author = cloned_authors.pop(0)
                cloned_authors.append(first_author)
                new_book = deepcopy(book)
                new_book['author'] = '    &    '.join(cloned_authors)
                new_book['authors'] = list(cloned_authors)
                asl = [author_to_author_sort(auth) for auth in cloned_authors]
                new_book['author_sort'] = '    &    '.join(asl)
                books_by_author.append(new_book)
    return books_by_author
