diff --git a/rwx/prj/sphinx.py b/rwx/prj/sphinx.py
index 3cef334..afa0901 100644
--- a/rwx/prj/sphinx.py
+++ b/rwx/prj/sphinx.py
@@ -1,3 +1,5 @@
+"""Project consisting only of a Sphinx documentation."""
+
 from os import path
 
 from sphinx.cmd.build import build_main
@@ -10,7 +12,7 @@ class SphinxProject(Project):
     def __init__(self, file_path: str) -> None:
         super().__init__(file_path)
 
-    def build(self):
+    def build(self) -> None:
         output_root: str = path.join(self.root, "out")
         wipe(output_root)
         arguments: list[str] = [