diff --git a/notebooks/Gotthard2/Characterize_Darks_Gotthard2_NBC.ipynb b/notebooks/Gotthard2/Characterize_Darks_Gotthard2_NBC.ipynb
index 8996ae9737aabc63dabe2ac1cdbbb1e53a62e5ce..3a1edb65e7aa4b7208ec5886b500a9afc9c0c559 100644
--- a/notebooks/Gotthard2/Characterize_Darks_Gotthard2_NBC.ipynb
+++ b/notebooks/Gotthard2/Characterize_Darks_Gotthard2_NBC.ipynb
@@ -227,7 +227,7 @@
     "    # Filter DA connected to detector in CALCAT\n",
     "    karabo_da = [da for da in karabo_da if da in da_to_pdu]\n",
     "else:\n",
-    "    karabo_da = da_to_pdu.keys()\n",
+    "    karabo_da = list(da_to_pdu.keys())\n",
     "\n",
     "print(f\"Processing {karabo_da}\")"
    ]