for ebook_format in Book.ebook_formats:
if os.path.isfile(file_base + '.' + ebook_format):
getattr(book, '%s_file' % ebook_format).save(
for ebook_format in Book.ebook_formats:
if os.path.isfile(file_base + '.' + ebook_format):
getattr(book, '%s_file' % ebook_format).save(