1 files changed, 2 insertions, 2 deletions
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index a13f11f8d8..d55b93d763 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -13,11 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import json
 import logging
 import re
 
 import attr
-from canonicaljson import json
 
 from twisted.internet import defer, task
 
@@ -45,7 +45,7 @@ def unwrapFirstError(failure):
     return failure.value.subFailure
 
 
-@attr.s
+@attr.s(slots=True)
 class Clock:
     """
     A Clock wraps a Twisted reactor and provides utilities on top of it.