Fix notebook facade usage

docs/tutorials/facade-usage.ipynb

@@ -156,8 +156,6 @@
     "        capacity=100,\n",
     "        marginal_cost=25,\n",
     "        output_parameters={\n",
-    "            'min': 0.1,\n",
-    "            'max': 0.9,\n",
     "            'summed_min': 1000,\n",
     "            'summed_max': 2000}\n",
     "    )\n",
@@ -195,6 +193,22 @@
     ")\n"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Add the subnodes of the Reservoir to energy system (hopefully soon obsolete). When reading from datapackage resource this is not necessary as the datapackage reader takes care of this."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "es.add(*es.groups['rsv'].subnodes)"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},