diff --git a/adafruit_st7735.py b/adafruit_st7735.py
index 7103e6b..8cb804d 100755
--- a/adafruit_st7735.py
+++ b/adafruit_st7735.py
@@ -52,5 +52,5 @@
 class ST7735(displayio.Display):
     """ST7735 driver"""
 
-    def __init__(self, bus, **kwargs):
+    def __init__(self, bus: displayio.FourWire, **kwargs) -> None:
         super().__init__(bus, _INIT_SEQUENCE, **kwargs)