diff --git a/acme/acme/challenges.py b/acme/acme/challenges.py
index 3fa259b13..a5b142c5b 100644
--- a/acme/acme/challenges.py
+++ b/acme/acme/challenges.py
@@ -226,7 +226,6 @@ class DNS01Response(KeyAuthorizationChallengeResponse):
         :param unicode domain: Domain name being verified.
         :param account_public_key: Public key for the key pair
             being authorized.
-        :param JWK account_public_key:
 
         :returns: ``True`` iff validation with the TXT records resolved from a
             DNS server is successful.
diff --git a/acme/acme/dns_resolver_test.py b/acme/acme/dns_resolver_test.py
index 2202ce4e8..0d5cc2543 100644
--- a/acme/acme/dns_resolver_test.py
+++ b/acme/acme/dns_resolver_test.py
@@ -1,11 +1,17 @@
 """Tests for acme.dns_resolver."""
 import unittest
 
-import dns
 import mock
 
+try:
+    import dns
+except ImportError:
+    dns = None
+
 from acme import dns_resolver
 
+@unittest.skipIf(dns is None,
+                 "dnspython is not available, skipping dns_resolver tests")
 class TxtRecordsForNameTest(unittest.TestCase):
 
     def create_txt_response(self, name, txt_records):