[O] accessing properties in org-element-parse-buffer tree

[Eike]

Hello list,

I want to ask for help regarding elisp and org-elements. I like to
access the properties of all my headlines and I created the following
function (tree is the parsed tree) that collects them into an a-list:

#+begin_src emacs-lisp
  (defun collect-props (tree)
    (car (org-element-map tree 'headline
           (lambda (hl)
             (when (eq 2 (org-element-property :level hl)) ; want only level-2 
properties
               (org-element-map hl 'node-property
                 (lambda (np)
                   (cons (org-element-property :key np)
                         (org-element-property :value np)))))))))
#+end_src

I'm not very confident about this, is this ok? Is there a better way?
For example, the first car looks strange, and I don't know how to get
rid of it.

Thanks you very much in advance!!!
Kind regards
Eike

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