Clearly document that this is a good example
diff --git a/docs/hazmat/primitives/symmetric-encryption.rst b/docs/hazmat/primitives/symmetric-encryption.rst
index 309c6fd..d588489 100644
--- a/docs/hazmat/primitives/symmetric-encryption.rst
+++ b/docs/hazmat/primitives/symmetric-encryption.rst
@@ -334,6 +334,9 @@
 
     :raises ValueError: This is raised if ``len(tag) < min_tag_length``.
 
+    An example of securely encrypting and decrypting data with ``AES`` in the
+    ``GCM`` mode looks like:
+
     .. testcode::
 
         import os