give filter default value
diff --git a/plstackapi/planetstack/api/roles.py b/plstackapi/planetstack/api/roles.py
index c181adf..12a21b8 100644
--- a/plstackapi/planetstack/api/roles.py
+++ b/plstackapi/planetstack/api/roles.py
@@ -25,7 +25,7 @@
     role.delete()
     return 1
 
-def get_roles(auth, filter):
+def get_roles(auth, filter={}):
     client = auth_check(auth)
     roles = Role.objects.filter(**filter)
     return roles