Update app.py

app.py

@@ -38,7 +38,7 @@ def apply_filter(img, filters):
         np.maximum(newimage, image_filter, newimage)
     return newimage
 
-def greet(image, in_contrast, in_brightness):
+def greet(image, in_contrast=1, in_brightness=0):
     in_contrast = float(in_contrast)
     in_brightness = float(in_brightness)
     # contrast [1.0-3.0]