diff --git a/rwx/fs/__init__.py b/rwx/fs/__init__.py
index e769358..c91e0b8 100644
--- a/rwx/fs/__init__.py
+++ b/rwx/fs/__init__.py
@@ -1,3 +1,5 @@
+"""Operations involving FileSystems."""
+
 import os
 import shutil
 
@@ -6,7 +8,8 @@ from rwx import ps
 CHARSET = "UTF-8"
 
 
-def create_image(file_path: str, size_bytes: int):
+def create_image(file_path: str, size_bytes: int) -> None:
+    """Create a virtual device image file."""
     ps.run(
         ("qemu-img", "create"),
         ("-f", "qcow2"),
@@ -14,11 +17,13 @@ def create_image(file_path: str, size_bytes: int):
     )
 
 
-def empty_file(path: str):
+def empty_file(path: str) -> None:
+    """Empty the file at provided path."""
     write(path, "")
 
 
-def get_mount_uuid(path: str):
+def get_mount_uuid(path: str) -> str:
+    """Return the UUID of provided mountpoint path."""
     return ps.run_line(
         ("findmnt",),
         ("--noheadings",),