diff --git a/algorithms/qml/qgan/qgan_bars_and_strips.ipynb b/algorithms/qml/qgan/qgan_bars_and_strips.ipynb
index 255ad30a6..362eadc72 100644
--- a/algorithms/qml/qgan/qgan_bars_and_strips.ipynb
+++ b/algorithms/qml/qgan/qgan_bars_and_strips.ipynb
@@ -774,7 +774,7 @@
     "    )\n",
     "    if_(\n",
     "        condition=qbv.len > 2,\n",
-    "        then=lambda: RZZ(weights[-1], qbv[0:2]),\n",
+    "        then=lambda: RZZ(weights[weights.len - 1], qbv[0:2]),\n",
     "        else_=lambda: IDENTITY(qbv[0]),\n",
     "    )\n",
     "\n",