diff --git a/examples/units/basic_units.py b/examples/units/basic_units.py
index 2a8e94887e95..0e62db1233e6 100644
--- a/examples/units/basic_units.py
+++ b/examples/units/basic_units.py
@@ -154,6 +154,9 @@ def __str__(self):
     def __len__(self):
         return len(self.value)
 
+    def __getitem__(self, key):
+        return TaggedValue(self.value[key], self.unit)
+
     def __iter__(self):
         # Return a generator expression rather than use `yield`, so that
         # TypeError is raised by iter(self) if appropriate when checking for