Add the "Debug setting =org-babel-load-languages= options" section

README.org

@@ -2411,6 +2411,92 @@ else:
 |  -2 | [NO-PACKAGES]         |
 |  -3 | [NO-EXTRA]            |
 
+*** Debug setting =org-babel-load-languages= options
+:PROPERTIES:
+:CUSTOM_ID: sec:setopt-org-babel-load-languages
+:header-args:emacs-lisp: :exports code :tangle no
+:END:
+
+#+caption[Find valid entries for =org-babel-load-languages=]:
+#+caption: Find valid entries for  =org-babel-load-languages=.
+#+name: lst:valid-org-babel-load-languages-entries
+#+header: :wrap "src emacs-lisp :results silent :tangle no"
+#+begin_src emacs-lisp :exports both :results value pp :exports both
+(defun all-org-babel-execute-fns ()
+  "Find `ob-LANGUAGE' files in Org defining `org-babel-execute:LANGUAGE'.
+
+Return a list of items where the filename is the `car' of each item and the
+`cdr' of each item lists the `org-babel-execute:LANGUAGE' functions."
+  (let* ((dir (file-name-parent-directory (locate-library "org")))
+         (names (directory-files dir t (rx "ob-" (+ print)  ".el" eos))))
+    (cl-loop for name in names
+             for found = (has-org-babel-execute-fn name)
+             when found collect found)))
+
+(defun has-org-babel-execute-fn (name)
+  (let* ((buffer (find-file-noselect name))
+         (base (file-name-base (buffer-file-name buffer)))
+         (regexp (rx "defun" (+ blank) "org-babel-execute:" (group (+ graphic))))
+         (matches))
+    (save-match-data
+      (save-excursion
+        (with-current-buffer buffer
+          (save-restriction
+            (widen)
+            (goto-char 1)
+            (while (re-search-forward regexp nil t 1)
+              (push (match-string-no-properties 1) matches))))))
+    (when matches
+      `(,base ,@matches))))
+
+(all-org-babel-execute-fns)
+#+end_src
+
+#+caption[Org Babel libraries with =org-babel-execute:language= functions]:
+#+caption: Org Babel libraries with =org-babel-execute:language= functions.
+#+RESULTS: lst:valid-org-babel-load-languages-entries
+#+begin_src emacs-lisp :results silent :tangle no
+(("ob-C" "C" "D" "C++" "cpp")
+ ("ob-R" "R")
+ ("ob-awk" "awk")
+ ("ob-calc" "calc")
+ ("ob-clojure" "clojurescript" "clojure")
+ ("ob-css" "css")
+ ("ob-ditaa" "ditaa")
+ ("ob-dot" "dot")
+ ("ob-emacs-lisp" "emacs-lisp")
+ ("ob-eshell" "eshell")
+ ("ob-forth" "forth")
+ ("ob-fortran" "fortran")
+ ("ob-gnuplot" "gnuplot")
+ ("ob-groovy" "groovy")
+ ("ob-haskell" "haskell")
+ ("ob-java" "java")
+ ("ob-js" "js")
+ ("ob-julia" "julia")
+ ("ob-latex" "latex")
+ ("ob-lilypond" "lilypond")
+ ("ob-lisp" "lisp")
+ ("ob-lua" "lua")
+ ("ob-makefile" "makefile")
+ ("ob-maxima" "maxima")
+ ("ob-ocaml" "ocaml")
+ ("ob-octave" "octave" "matlab")
+ ("ob-org" "org")
+ ("ob-perl" "perl")
+ ("ob-plantuml" "plantuml")
+ ("ob-processing" "processing")
+ ("ob-python" "python")
+ ("ob-ruby" "ruby")
+ ("ob-sass" "sass")
+ ("ob-scheme" "scheme")
+ ("ob-screen" "screen")
+ ("ob-sed" "sed")
+ ("ob-shell" "shell")
+ ("ob-sql" "sql")
+ ("ob-sqlite" "sqlite"))
+#+end_src
+
 *** [[https://github.com/bdarcus/citar][Citar: citing bibliography]] with [[https://orgmode.org/][Org Mode]]
 :PROPERTIES:
 :CUSTOM_ID: sec:citing-bibliography
@@ -4565,6 +4651,10 @@ server, before plunging into the configuration steps:
 5. [[https://ddavis.io/posts/python-emacs-3/][Python & Emacs, Take 3]]
 6. [[https://ddavis.io/posts/emacs-python-lsp/][Python with Emacs: py(v)env and lsp-mode]]
 
+Videos
+1. [[yt:HTLu2DFOdTg][Python's Class Development Kit - Raymond Hettinger]]
+2.
+
 *** [[https://git.savannah.gnu.org/cgit/emacs.git/tree/lisp/progmodes/python.el][Python-mode]]
 :PROPERTIES:
 :CUSTOM_ID: sec:python-mode