Check for mask_values before popping

Author: rachthree

hubconf.py

@@ -15,7 +15,8 @@ def unet_carvana(pretrained=False, scale=0.5):
         else:
             raise RuntimeError('Only 0.5 and 1.0 scales are available')
         state_dict = torch.hub.load_state_dict_from_url(checkpoint, progress=True)
-        state_dict.pop('mask_values')
+        if 'mask_values' in state_dict:
+            state_dict.pop('mask_values')
         net.load_state_dict(state_dict)
 
     return net