From 3488e1fb837eac2d01dd6b88ce2d7b26e6b27008 Mon Sep 17 00:00:00 2001
From: Laurens Valk <laurens@pybricks.com>
Date: Fri, 10 Jul 2020 12:32:52 +0200
Subject: [PATCH] doc/pupdevices/UltrasonicSensor: document invalid

Document how invalid values are reported.
---
 pybricks/pupdevices.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pybricks/pupdevices.py b/pybricks/pupdevices.py
index cc054da..5f7a5eb 100644
--- a/pybricks/pupdevices.py
+++ b/pybricks/pupdevices.py
@@ -280,7 +280,8 @@ class UltrasonicSensor:
         ultrasonic sound waves.
 
         Returns:
-            :ref:`distance`: Distance.
+            :ref:`distance`: Measured distance. If no valid distance was
+            measured, it returns 2000 mm.
 
         """
         pass