diff --git a/docs/examples/actions/colorizer.py b/docs/examples/actions/colorizer.py
index 6a1fb5e4f..8ba59cfa6 100644
--- a/docs/examples/actions/colorizer.py
+++ b/docs/examples/actions/colorizer.py
@@ -2,13 +2,12 @@ from textual.app import App
 
 
 class Colorizer(App):
-
     async def on_load(self, event):
         await self.bind("r", "color('red')")
         await self.bind("g", "color('green')")
         await self.bind("b", "color('blue')")
 
-    async def action_color(self, color:str) -> None:
+    async def action_color(self, color: str) -> None:
         self.background = f"on {color}"