diff --git a/changelog.d/3534.misc b/changelog.d/3534.misc
new file mode 100644
index 0000000000..949c12dc69
--- /dev/null
+++ b/changelog.d/3534.misc
@@ -0,0 +1 @@
+refactor: use parse_{string,integer} and assert's from http.servlet for deduplication
diff --git a/synapse/rest/client/v1/directory.py b/synapse/rest/client/v1/directory.py
index c320612aea..69dcd618cb 100644
--- a/synapse/rest/client/v1/directory.py
+++ b/synapse/rest/client/v1/directory.py
@@ -18,7 +18,7 @@ import logging
 
 from twisted.internet import defer
 
-from synapse.api.errors import AuthError, SynapseError
+from synapse.api.errors import AuthError, Codes, SynapseError
 from synapse.http.servlet import parse_json_object_from_request
 from synapse.types import RoomAlias