Add python-black.

elisp/extras.el

@@ -179,6 +179,12 @@
   :init
   (setenv "WORKON_HOME" "~/.cache/pypoetry/virtualenvs"))
 
+(use-package python-black
+  :straight t
+  ;; :demand t
+  :after python
+  :hook (python-mode . python-black-on-save-mode-enable-dwim))
+
 ;; Ivy related stuff
 (use-package ivy)
 (use-package ivy-bibtex