Fix error caused by renaming Region to Zone

examples/ex6.ipynb

@@ -92,19 +92,21 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## Reginonal Design"
+    "## Zonal Design"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "The disaptch models in AMS has develoepd with regional structure, and it can be inspected in device ``Region``."
+    "The scheduling models in AMS has develoepd with zonal structure, and it can be inspected in device ``Zone``.\n",
+    "\n",
+    "**Note**: Since version 0.9.14, model ``Region`` is renamed to ``Zone`` for clarity."
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 5,
+   "execution_count": null,
    "metadata": {},
    "outputs": [
     {
@@ -169,7 +171,7 @@
     }
    ],
    "source": [
-    "sp.Region.as_df()"
+    "sp.Zone.as_df()"
    ]
   },
   {