Merge pull request adafruit#2344 from adafruit/TheKitty-patch-2

Fix index out of range error

Author: BlitzCityDIY

Trinket_Ultrasonic_Rangefinder/README.md

@@ -2,3 +2,5 @@
 
 Code to accompany this tutorial:
 https://learn.adafruit.com/trinket-ultrasonic-rangefinder
+
+Currently limited to M0 versions due to an issue in the Arduino IDE

Trinket_Ultrasonic_Rangefinder/code.py

@@ -81,6 +81,12 @@ def find_mode(x):
     """
     n = len(x)
 
+    if n == 0:  # If somehow there is a null array
+        return 0
+
+    if n == 1:       # In trivial case of a one element array
+        return x[0]  # just return the element as the mode.
+
     max_count = 0
     mode = 0
     bimodal = 0