On Wed, Sep 28, 2016 at 05:02:56PM +0000, ng0 wrote:
> Subject: [PATCH] gnu: Add python-mailmanclient.
> 
> * gnu/packages/mail.scm (python-mailmanclient): New variable.

> +(define-public python2-mailmanclient
> +  (let ((base (package-with-python2
> +               (strip-python2-variant python-mailmanclient))))
> +    (package (inherit base)
> +      (native-inputs
> +       `(("python2-setuptools" ,python2-setuptools))))))

This variant will not be used unless there is a python2-variant
properties field in python-mailman, like this:

(properties `((python2-variant . ,(delay python2-mailmanclient))))

You can see the recent commit "gnu: Add python-q. (e8c9b01090)" for an
example in context.