diff --git a/plugins/CuraEngineBackend/StartSliceJob.py b/plugins/CuraEngineBackend/StartSliceJob.py
index afbc816cc5..31ea999161 100644
--- a/plugins/CuraEngineBackend/StartSliceJob.py
+++ b/plugins/CuraEngineBackend/StartSliceJob.py
@@ -139,7 +139,7 @@ class StartSliceJob(Job):
 
         # Don't slice if there is a per object setting with an error value.
         for node in DepthFirstIterator(self._scene.getRoot()):
-            if type(node) is not CuraSceneNode or not node.isSelectable():
+            if not isinstance(node, CuraSceneNode) or not node.isSelectable():
                 continue
 
             if self._checkStackForErrors(node.callDecoration("getStack")):