Note source of exception.

tseaver · tseaver · commit 7441438f6940 · 2014-11-03T17:00:09.000-05:00
Incorporates feedback from @dhermes.
diff --git a/gcloud/storage/key.py b/gcloud/storage/key.py
@@ -165,7 +165,9 @@ def delete(self):
 
         :rtype: :class:`Key`
         :returns: The key that was just deleted.
-        :raises: :class:`gcloud.storage.exceptions.NotFoundError`.
+        :raises: :class:`gcloud.storage.exceptions.NotFoundError`
+                 (propagated from
+                 :meth:`gcloud.storage.bucket.Bucket.delete_key`).
         """
         return self.bucket.delete_key(self)
 
