diff --git a/src/Year_2016/P8.py b/src/Year_2016/P8.py
index 879ad19..c47b794 100644
--- a/src/Year_2016/P8.py
+++ b/src/Year_2016/P8.py
@@ -117,7 +117,7 @@ def part_1() -> None:
 # After you swipe your card, what code is the screen trying to display?
 
 
-def display(grid):
+def display(grid: npt.NDArray[int]) -> None:
     print(
         "\n".join("".join("X" if one else " " for one in row) for row in grid)
     )