diff --git a/notebooks/ePix100/Correction_ePix100_NBC.ipynb b/notebooks/ePix100/Correction_ePix100_NBC.ipynb
index 7bc7b208d40caeaa113209437e42e73eb95d7105..7df412a554a1085f02602fd7f75e4f913b4e575d 100644
--- a/notebooks/ePix100/Correction_ePix100_NBC.ipynb
+++ b/notebooks/ePix100/Correction_ePix100_NBC.ipynb
@@ -635,11 +635,12 @@
     "            \"data.trainId\", data=seq_dc.train_ids, chunks=min(50, len(seq_dc.train_ids)))\n",
     "        \n",
     "        if np.isin('data.pulseId', list(seq_dc[instrument_src].keys())): # some runs are missing 'data.pulseId'\n",
-    "            pulse_ids = seq_dc[instrument_src]['data.pulseId'].ndarray().squeeze().tolist()\n",
-    "            if isinstance(pulse_ids, int):  # one pulse in case of correcting one train\n",
-    "                pulse_ids = [pulse_ids]\n",
+    "            pulseid = seq_dc[instrument_src]['data.pulseId'].ndarray().squeeze()\n",
+    "            # pulseid is scalar for one train.\n",
+    "            pulseid = [pulseid] if not pulseid.shape else list(pulseid)\n",
+    "\n",
     "            outp_source.create_key(\n",
-    "                \"data.pulseId\", data=pulse_ids, chunks=min(50, len(seq_dc.train_ids)))\n",
+    "                \"data.pulseId\", data=pulseid, chunks=min(50, len(seq_dc.train_ids)))\n",
     "        \n",
     "        if pattern_classification:\n",
     "            # Add main corrected `data.image.pixels` dataset and store corrected data.\n",