try:
epub.transform(BookImportDocProvider(self), self.slug, epub_file)
self.epub_file.save('%s.epub' % self.slug, ContentFile(epub_file.getvalue()), save=False)
try:
epub.transform(BookImportDocProvider(self), self.slug, epub_file)
self.epub_file.save('%s.epub' % self.slug, ContentFile(epub_file.getvalue()), save=False)