diff --git a/docs/lib3x-hashmap_get.md b/docs/lib3x-hashmap_get.md
index 2d46b9c6..75916cee 100644
--- a/docs/lib3x-hashmap_get.md
+++ b/docs/lib3x-hashmap_get.md
@@ -1,6 +1,6 @@
 # hashmap_get
 
-This function gets the value of the specified key from a [util/map/hashmap](https://openhome.cc/eGossip/OpenSCAD/lib3x-hashmap.html).
+This function gets the value of the specified key from a [util/map/hashmap](https://openhome.cc/eGossip/OpenSCAD/lib3x-hashmap.html). If the key doesn't exist, return `undef`.
 
 **Since:** 3.0