I don't understand how to extract todo-keyword values from a headline using
org-element-property.

I am trying something like this:

 (org-element-map (org-element-parse-buffer) 'headline
         (lambda (item)
           (print (nth 0 (org-element-property :todo-keyword item)))
            (when (eq (org-element-property :todo-keyword item) "READY")