diff --git a/configurations/values.py b/configurations/values.py
index b212615..8eb233e 100644
--- a/configurations/values.py
+++ b/configurations/values.py
@@ -165,7 +165,7 @@ class BackendsValue(ListValue):
     def converter(self, value):
         try:
             import_by_path(value)
-        except ImproperlyConfigured, err:
+        except ImproperlyConfigured as err:
             six.reraise(ValueError, ValueError(err), sys.exc_info()[2])
         return value