diff --git a/README.org b/README.org
index 2661b8c..e0843e5 100644
--- a/README.org
+++ b/README.org
@@ -1238,7 +1238,7 @@ sub makeglossaries {
       (with-current-buffer buffer
         (let ((mode major-mode))
           (push mode result))))
-    (cl-sort (cl-remove-duplicates result) #'string-lessp)))
+    (sort (cl-remove-duplicates result))))
 #+end_src
 
 
@@ -1977,9 +1977,9 @@ configuration objectives:
   (defun update-lualatex-opentype-font-name-database ()
     "Update the \"OpenType Font\" name database for \"LuaLaTeX\"."
     (interactive)
-    (cl-destructuring-bind (exit-code output)
-        (shell-command-with-exit-code
-         "luaotfload-tool" "-vv" "--update" "--force")
+    (pcase-let ((`(,exit-code ,output)
+                 (shell-command-with-exit-code
+                  "luaotfload-tool" "-vv" "--update" "--force")))
       (if (= 0 exit-code)
           (message "%s" (string-trim output))
         (error "%s" (string-trim output))))))
@@ -2529,7 +2529,7 @@ def __org_babel_python_format_value(result, result_file, result_params):
                  result)))))
     result))
 
-(mapcar #'list (cl-sort (org-babel-active-languages) #'string-lessp))
+(mapcar #'list (sort (org-babel-active-languages)))
 #+end_src
 
 #+caption[Active Org Babel languages]:
@@ -2642,8 +2642,8 @@ valid directories and files.  In an [[https://orgmode.org/][Org-mode]] buffer th
   (defun biber-delete-cache ()
     "Delete the `Biber' cache to get rid of `Biber' exit code 2."
     (interactive)
-    (cl-destructuring-bind (exit-code output)
-        (shell-command-with-exit-code "rm" "-rf" "$(biber --cache)")
+    (pcase-let ((`(,exit-code ,output)
+                 (shell-command-with-exit-code "rm" "-rf" "$(biber --cache)")))
       (if (= 0 exit-code)
           (message "%s" (string-trim output))
         (error "%s" (string-trim output))))))
@@ -4867,40 +4867,38 @@ through =cat= to remove escape sequences.
 (when (executable-find "pyenv")
   (defun pyenv-full-path (version)
     "Return the full path for VERSION."
-    (unless (string= version "system")
-      (concat (pyenv-root) (file-name-as-directory "versions") version)))
+    (concat (pyenv-root) (file-name-as-directory "versions") version))
 
   (defun pyenv-root ()
     "Return \"pyenv root\" as a directory."
-    (cl-destructuring-bind (exit-code output)
-        (shell-command-with-exit-code "pyenv" "root")
+    (pcase-let ((`(,exit-code ,output)
+                 (shell-command-with-exit-code "pyenv" "root")))
       (if (= 0 exit-code)
           (file-name-as-directory (string-trim output))
         (error "%s" (string-trim output)))))
 
   (defun pyenv-version-name ()
     "Return \"pyenv version-name\"."
-    (cl-destructuring-bind (exit-code output)
-        (shell-command-with-exit-code "pyenv" "version-name")
+    (pcase-let ((`(,exit-code ,output)
+                 (shell-command-with-exit-code "pyenv" "version-name")))
       (if (= 0 exit-code)
           (string-trim output)
         (error "%s" (string-trim output)))))
 
   (defun pyenv-versions ()
-    "Return \"pyenv versions --bare --skip-aliases\" as a list.
-Complete the result with \"system\"."
-    (cl-destructuring-bind (exit-code output)
-        (shell-command-with-exit-code
-         "pyenv" "versions" "--bare" "--skip-aliases")
+    "Return \"pyenv versions --bare --skip-aliases\" as a list."
+    (pcase-let ((`(,exit-code ,output)
+                 (shell-command-with-exit-code
+                  "pyenv" "versions" "--bare" "--skip-aliases")))
       (if (= 0 exit-code)
-          (cons "system" (split-string output))
+          (split-string output)
         (error "%s" (string-trim output)))))
 
   (defun pyenv-virtualenvs ()
     "Return \"pyenv virtualenvs --bare --skip-aliases\" as a list."
-    (cl-destructuring-bind (exit-code output)
-        (shell-command-with-exit-code
-         "pyenv" "virtualenvs" "--bare" "--skip-aliases")
+    (pcase-let ((`(,exit-code ,output)
+                 (shell-command-with-exit-code
+                  "pyenv" "virtualenvs" "--bare" "--skip-aliases")))
       (if (= 0 exit-code)
           (split-string output)
         (error "%s" (string-trim output))))))
@@ -4911,10 +4909,10 @@ Complete the result with \"system\"."
 #+name: lst:select-python-virtual-environment
 #+begin_src emacs-lisp -n :results silent
 (with-eval-after-load 'python
-  (when (cl-every #'fboundp '(pyenv-full-path
-                              pyenv-version-name
-                              pyenv-versions
-                              pyenv-virtualenvs))
+  (when (and (fboundp 'pyenv-full-path)
+             (fboundp 'pyenv-version-name)
+             (fboundp 'pyenv-versions)
+             (fboundp 'pyenv-virtualenvs))
     (setq python-shell-virtualenv-root
           (pyenv-full-path (or (pyenv-version-name)
                                (car (pyenv-virtualenvs))
@@ -4923,7 +4921,7 @@ Complete the result with \"system\"."
              python-shell-virtualenv-root)
 
     (defun set-python-shell-virtualenv-root-to-pyenv-version ()
-      "Set `python-shell-virtual-env-root' to a pyenv version."
+      "Set `python-shell-virtualenv-root' to a pyenv version."
       (interactive)
       (let* ((version-name (pyenv-version-name))
              (prompt (format "pyenv version (%s): " version-name))
@@ -4936,7 +4934,7 @@ Complete the result with \"system\"."
                  python-shell-virtualenv-root)))
 
     (defun set-python-shell-virtualenv-root-to-pyenv-virtualenv ()
-      "Set `python-shell-virtual-env-root' to a pyenv virtualenv."
+      "Set `python-shell-virtualenv-root' to a pyenv virtualenv."
       (interactive)
       (let* ((version-name (pyenv-version-name))
              (prompt (format "pyenv virtualenv (%s): " version-name))