diff --git a/adafruit_ssd1351.py b/adafruit_ssd1351.py
index 21af0e7..3a2305b 100755
--- a/adafruit_ssd1351.py
+++ b/adafruit_ssd1351.py
@@ -58,7 +58,7 @@
 class SSD1351(displayio.Display):
     """SSD1351 driver"""
 
-    def __init__(self, bus, **kwargs):
+    def __init__(self, bus: displayio.FourWire, **kwargs) -> None:
         super().__init__(
             bus,
             _INIT_SEQUENCE,