From 41466be0079c85f004dd5ee40080a95014e4a23e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rodrigo=20Gir=C3=A3o=20Serr=C3=A3o?=
 <5621605+rodrigogiraoserrao@users.noreply.github.com>
Date: Tue, 9 May 2023 17:10:08 +0100
Subject: [PATCH] Add docstrings.

---
 src/textual/app.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/textual/app.py b/src/textual/app.py
index e5987f857..12f66cf04 100644
--- a/src/textual/app.py
+++ b/src/textual/app.py
@@ -409,9 +409,11 @@ class App(Generic[ReturnType], DOMNode):
         self.set_class(not self.dark, "-light-mode")
 
     def validate_title(self, title: Any) -> str:
+        """Make sure the title is set to a string."""
         return str(title)
 
     def validate_sub_title(self, sub_title: Any) -> str:
+        """Make sure the sub-title is set to a string."""
         return str(sub_title)
 
     @property