Fix callable syntax

Author: alan412

external_samples/rev_touch_sensor.py

@@ -26,9 +26,10 @@ def is_pressed(self) -> bool:
         return True
 
     # Events
-    def when_pressed_register(callback: Callable[[None, None]]) -> None:
+    def when_pressed_register(callback: Callable[[], None]) -> None:
         # Code to register callback here
         pass
-    def when_released_register(callback: Callable[[None, None]]) -> None:
+
+    def when_released_register(callback: Callable[[], None]) -> None:
         # Code to register callback here
         pass