org-element is a new module for org-mode, I think it is good for parse org file, and don't want to parse it by old way with match-string. but after play with it for some hours, I have to admit I don't have enough experience with org-mode, so could masters give me some clues, thanks very much!

My requirement is simple, I want to get all headlines and content.

* headline

:PROPERTIES

** subheadline

content1

** subheadline

content2
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