docs: def make_publication_epub(binders, publisher, publication_message, file):
      """Creates an epub file from a binder(s). Also requires
      publication information, meant to be used in a EPUB publication
      request.
      """
      if not isinstance(binders, (list, set, tuple,)):
          binders = [binders]
      packages = []
      for binder in binders:
          metadata = binder.metadata
          binder.metadata = deepcopy(metadata)
          binder.metadata.update({'publisher': publisher,
                                  'publication_message': publication_message})
          packages.append(_make_package(binder))
          binder.metadata = metadata
      epub = EPUB(packages)
      epub.to_file(epub, file)