Use black formatting

README.md

@@ -83,6 +83,19 @@ Python AES library, but I doubt it.
 The password is stored in plaintext in `~/.config/sync-mpv/serverpassword.conf`.
 This thing actually appears to work, wow.
 
+# Development
+To "develop", install the requirements:
+
+```
+pip install -r requirements-dev.txt
+```
+
+Then run `black` on the Python files for nice formatting:
+
+```
+black *.py
+```
+
 
 # Upstream
 ## sync-mpv