give context for ipynb

Author: MatthewCaseres

low-level-api-proposal.ipynb

@@ -6,6 +6,8 @@
    "source": [
     "# Background\n",
     "\n",
+    "**This notebook was authored when I was trying to figure out the structure of the XML so I could write the API**\n",
+    "\n",
     "## XTbML\n",
     "\n",
     "An XML standard for representing mortality tables called XTbML was developed in a joint effort between the Technology Section of the SOA and the standards-setting body ACORD. For more information, read [this](https://www.soa.org/news-and-publications/newsletters/compact/2013/april/com-2013-iss47/tables-database-goes-xtbml/).\n",