Update app.py

app.py

@@ -24,6 +24,7 @@ def midpoint(x1, y1, x2, y2):
 def draw_mask(img, bounds):
     mask = np.zeros(img.shape[:2], dtype="uint8")
     for bound in bounds:
+        box0, box1, box2, box3 = bound[0]
         
         x0, y0 = box0
         x1, y1 = box1