def formatsWritersField(writers_list):
    """ Formats Writers field for Web app template. """
    
    film_writers=""
    if writers_list != None:
        for writer in writers_list:
            if len(writers_list) == 1 or writer == writers_list[-2]:
                film_writers = writer
            elif writer != writers_list[-1] and writer != writers_list[-2]:
                film_writers += writer + ", "
            elif writer == writers_list[-1]:
                film_writers += " & " + writer 
    else:
        film_writers = "Unknown"
    return film_writers