diff --git a/examples/pfield.ipynb b/examples/pfield.ipynb
index 72b78df..7a1c291 100644
--- a/examples/pfield.ipynb
+++ b/examples/pfield.ipynb
@@ -247,6 +247,15 @@
     "\n"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "P, _, _  = pymust.pfield(x,y, z,txdel,param)"
+   ]
+  },
   {
    "attachments": {},
    "cell_type": "markdown",