Update app.py

app.py

@@ -10,7 +10,7 @@ def greet(image, in_contrast, in_brightness):
     new_image = cv2.convertScaleAbs(image, alpha=in_contrast, beta=in_brightness)
 
     cv2.imshow("Display window", new_image);
-    int k = waitKey(0); // Wait for a keystroke in the window
+    cv2.waitKey(0)
     return new_image