diff --git a/packages/python/plotly/plotly/tests/test_core/test_errors/test_dict_path_errors.py b/packages/python/plotly/plotly/tests/test_core/test_errors/test_dict_path_errors.py
index 8b899a6f5..6ee06e03f 100644
--- a/packages/python/plotly/plotly/tests/test_core/test_errors/test_dict_path_errors.py
+++ b/packages/python/plotly/plotly/tests/test_core/test_errors/test_dict_path_errors.py
@@ -402,7 +402,7 @@ template_layout_plot_bgcolor_x
         print(e.args[0])
         e_substr = error_substr(
             e.args[0],
-            """string indices must be integers
+            """string indices must be integers, not 'str'
 
 Invalid value received for the 'plot_bgcolor' property of layout