diff --git a/GUIDE.md b/GUIDE.md
index 46cf79f..74a9018 100644
--- a/GUIDE.md
+++ b/GUIDE.md
@@ -53,3 +53,8 @@ class Mycheat(Hack):
 - See the [utils](./utils.py) file if you need more tools, like a vector class,
   colour etc.
 - If needed, feel free to add your own offsets to the `self.offsets` variable
+
+# Miscellaneous
+
+Please, use `black` before doing a pull request, as it's the formatter the
+project use.