Hi all,

I am starting to write a CC BY-SA 4.0 textbook and I want to be able to
write it in org-mode and publish it on leanpub.

I have hit some problems. I install org-mode on emacs 25.1 from
http://orgmode.org/elpa/ like this

(use-package org
  :ensure org-plus-contrib
  :defer t)

(require 'ox-md)

If I try to export the draft of my book

  https://raw.githubusercontent.com/fommil/fp-scala-mortals/master/book.org

using C-c C-e and select m m (Markdown), I get this error:

  Debugger entered--Lisp error: (wrong-type-argument listp #("2017" 0 4 (:parent (#1))))
    org-element-set-contents(#("2017" 0 4 (:parent (#0))))
    apply(org-element-set-contents #("2017" 0 4 (:parent (#0))) nil)


If I revert back to the version of ox-md that comes with Emacs 25.1, the
file is exported ok.


However, further to this. If I (require 'ox-leanpub) and C-c C-e using
the default version of org-mode, then the option to export to Leanpub
does not appear. Could somebody who knows how to write exporters
please have a look over

  https://raw.githubusercontent.com/juanre/ox-leanpub/master/ox-leanpub.el

to see if they can spot any obvious problems?

If I install ox-leanpub with the latest org-plus-contrib then the
:export-block line must be removed or it will fail to load.