diff --git a/src/building.js b/src/building.js
index 29fc255..c2949cc 100644
--- a/src/building.js
+++ b/src/building.js
@@ -98,6 +98,8 @@ class Building {
   /**
    * build an array of all the lat/long values of the nodes
    *
+   * @param {DOMDocument} fullXmlData
+   *
    * @return {[[number, number]]} array of coordinate pairs keyed by node id.
    */
   static buildNodeList(fullXmlData) {