diff --git a/inkycal/display/display.py b/inkycal/display/display.py
index e9fd834..5fb6420 100644
--- a/inkycal/display/display.py
+++ b/inkycal/display/display.py
@@ -54,7 +54,7 @@ class Display:
         raise NotImplementedError("Devs were too lazy again, sorry, please try again later")
 
 
-    def render(self, im_black: PIL.Image, im_colour: PIL.Image or None) -> None:
+    def render(self, im_black: PIL.Image, im_colour: PIL.Image or None=None) -> None:
         """Renders an image on the selected E-Paper display.
 
         Initlializes the E-Paper display, sends image data and executes command