Update example notebook to import UndateInterval from new location

Author: rlskoeser

examples/notebooks/shxco_partial_date_durations.ipynb

@@ -316,14 +316,14 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": 1,
    "metadata": {
     "id": "y_MqgrQW64uI"
    },
    "outputs": [],
    "source": [
+    "from undate import UndateInterval\n",
     "from undate.date import ONE_DAY\n",
-    "from undate.undate import UndateInterval\n",
     "from undate.converters.iso8601 import ISO8601DateFormat\n",
     "\n",
     "def undate_duration(start_date, end_date):\n",