diff --git a/rwx/deb/__init__.py b/rwx/deb/__init__.py
index e9c6a9e..f022ca5 100644
--- a/rwx/deb/__init__.py
+++ b/rwx/deb/__init__.py
@@ -1,3 +1,5 @@
+"""Wrap Debian commands."""
+
 import cmd
 
 import ps
@@ -8,7 +10,8 @@ BOOTSTRAP_ARCHITECTURE = "amd64"
 BOOTSTRAP_VARIANT = "minbase"
 
 
-def bootstrap(root_path: str, suite: str, mirror_location: str):
+def bootstrap(root_path: str, suite: str, mirror_location: str) -> None:
+    """Boostrap a base operating filesystem."""
     command = [
         ("debootstrap",),
         ("--arch", BOOTSTRAP_ARCHITECTURE),