diff --git a/trial.ipynb b/trial.ipynb
index 7f5aa04..479292c 100644
--- a/trial.ipynb
+++ b/trial.ipynb
@@ -306,12 +306,31 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 12,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "ename": "NameError",
+     "evalue": "name 'a' is not defined",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mNameError\u001b[0m                                 Traceback (most recent call last)",
+      "\u001b[1;32m/Users/chemlab/Documents/Coding/LearningAiiDa/aiida-aimall/trial.ipynb Cell 16\u001b[0m line \u001b[0;36m1\n\u001b[0;32m----> <a href='vscode-notebook-cell:/Users/chemlab/Documents/Coding/LearningAiiDa/aiida-aimall/trial.ipynb#X22sZmlsZQ%3D%3D?line=0'>1</a>\u001b[0m a\n",
+      "\u001b[0;31mNameError\u001b[0m: name 'a' is not defined"
+     ]
+    }
+   ],
    "source": [
     "a"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
   }
  ],
  "metadata": {