diff --git a/sciunit/utils.py b/sciunit/utils.py
index 5d5f27e..b48602a 100644
--- a/sciunit/utils.py
+++ b/sciunit/utils.py
@@ -26,7 +26,7 @@
 import nbformat
 from IPython.display import HTML, display
 from nbconvert.preprocessors import ExecutePreprocessor
-from nbconvert.preprocessors.execute import CellExecutionError
+from nbclient.exceptions import CellExecutionError
 from quantities.dimensionality import Dimensionality
 from quantities.quantity import Quantity