diff --git a/letsencrypt/client.py b/letsencrypt/client.py
index d0bdb1f85..6134c4e6e 100644
--- a/letsencrypt/client.py
+++ b/letsencrypt/client.py
@@ -163,7 +163,7 @@ class Client(object):
         dispatch DV challenges to appropriate authenticators
         (providing `.IAuthenticator` interface).
     :ivar .IAuthenticator auth: Prepared (`.IAuthenticator.prepare`)
-        authenticator that can solve the `.constants.DV_CHALLENGES`.
+        authenticator that can solve ACME challenges.
     :ivar .IInstaller installer: Installer.
     :ivar acme.client.Client acme: Optional ACME client API handle.
        You might already have one from `register`.