diff --git a/synapse/rest/client/v2_alpha/register.py b/synapse/rest/client/v2_alpha/register.py
index 7b97a73df..93f922370 100644
--- a/synapse/rest/client/v2_alpha/register.py
+++ b/synapse/rest/client/v2_alpha/register.py
@@ -224,7 +224,9 @@ class RegisterRestServlet(RestServlet):
             if k not in body:
                 absent.append(k)
 
-        existingUid = self.hs.get_datastore().get_user_id_by_threepid('email', body['email'])
+        existingUid = self.hs.get_datastore().get_user_id_by_threepid(
+            'email', body['email']
+        )
         if existingUid is not None:
             raise SynapseError(400, "Email is already in use", Codes.THREEPID_IN_USE)