From f7860bca482ab8af1a6be3279fe6b11a364df613 Mon Sep 17 00:00:00 2001
From: Umair Khan <umair.waheed@gmail.com>
Date: Fri, 24 Mar 2017 12:45:21 +0500
Subject: [PATCH] backends.py: Don't pass mutable default arguments.

Values of mutable default arguments are shared across all function
invocations. See
https://pythonconquerstheuniverse.wordpress.com/2012/02/15/mutable-default-arguments/
for further details.
---
 zproject/backends.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/zproject/backends.py b/zproject/backends.py
index b70eb6c337..64e58b833d 100644
--- a/zproject/backends.py
+++ b/zproject/backends.py
@@ -266,8 +266,11 @@ class GoogleMobileOauth2Backend(ZulipAuthMixin):
 
     """
 
-    def authenticate(self, google_oauth2_token=None, realm_subdomain=None, return_data={}):
-        # type: (Optional[str], Optional[Text], Dict[str, Any]) -> Optional[UserProfile]
+    def authenticate(self, google_oauth2_token=None, realm_subdomain=None, return_data=None):
+        # type: (Optional[str], Optional[Text], Optional[Dict[str, Any]]) -> Optional[UserProfile]
+        if return_data is None:
+            return_data = {}
+
         try:
             token_payload = googleapiclient.verify_id_token(google_oauth2_token, settings.GOOGLE_CLIENT_ID)
         except AppIdentityError: