diff --git a/example/trade_derivatives_en.ipynb b/example/trade_derivatives_en.ipynb
index 409a2e0..db5438a 100644
--- a/example/trade_derivatives_en.ipynb
+++ b/example/trade_derivatives_en.ipynb
@@ -46,7 +46,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": null,
    "metadata": {
     "pycharm": {
      "name": "#%%\n"