modified error in reporting unexpeced backgroundimage

server.py

@@ -68,7 +68,7 @@ class SegmenterBackground():
             print("replace effect")
 
         else:
-            raise ValueError("Got unexpected Input in background_image "+background_image)
+            raise ValueError("Got unexpected Input in background_image "+str(background_image))
 
         # Replace the background in the output image with the raw image where the mask is True
         outpt[mask_rgb] = np.array(raw_image)[mask_rgb]