diff --git a/packages/python/plotly/plotly/express/_core.py b/packages/python/plotly/plotly/express/_core.py
index 6f3d55dc5c9..22ea56c25a0 100644
--- a/packages/python/plotly/plotly/express/_core.py
+++ b/packages/python/plotly/plotly/express/_core.py
@@ -1131,7 +1131,7 @@ def process_args_into_dataframe(args, wide_mode, var_name, value_name):
             else args.get(field_name)
         )
         # argument not specified, continue
-        if argument_list is None or argument_list is [None]:
+        if argument_list is None or argument_list == [None]:
             continue
         # Argument name: field_name if the argument is not a list
         # Else we give names like ["hover_data_0, hover_data_1"] etc.