diff --git a/notebooks/part2.ipynb b/notebooks/part2.ipynb
index 1c4c366..efb084d 100644
--- a/notebooks/part2.ipynb
+++ b/notebooks/part2.ipynb
@@ -344,7 +344,7 @@
     "        if (len (cand2[-1]) == 1):\n",
     "            newCandidate.append(cand2[-1])\n",
     "        else:\n",
-    "            newCandidate [-1].extend(cand2[-1][-1])\n",
+    "            newCandidate [-1].extend([cand2[-1][-1]])\n",
     "        return newCandidate"
    ]
   },