If I have a document what looks like the following. What code could I run for the ??? to get the property value for "workspace-directory" that is closest in the outline to the location running the code?  :PROPERTIES:
  :workspace-directory: /tmp
  :END:
 
   #+begin_src emacs-lisp
     (???) ; /tmp
   #+end_src
   
** L2 Heading
   :PROPERTIES:
   :workspace-directory: ~/whatever
   :END:
   
   #+begin_src emacs-lisp
     (???) ; "~/whatever"
   #+end_src
 
** Another L2 Heading
   
   #+begin_src emacs-lisp
     (???) ; /tmp
   #+end_src