Changes after review. Updates to style and import order to be more consistent with other code.

Added clarification to an error message to give better debugging information.
Removed using dao_get_reply_to_by_service_id in tests to be more consistent with other code and use the test db functions or remove the need for a call altogether making the code less complex.

app/dao/notifications_dao.py

@@ -40,7 +40,9 @@ from app.models import (
     KEY_TYPE_NORMAL, KEY_TYPE_TEST,
     LETTER_TYPE,
     NOTIFICATION_SENT,
-    NotificationEmailReplyTo, ServiceEmailReplyTo)
+    NotificationEmailReplyTo,
+    ServiceEmailReplyTo
+)
 
 from app.dao.dao_utils import transactional
 from app.statsd_decorators import statsd
@@ -619,7 +621,7 @@ def dao_get_notification_email_reply_for_notification(notification_id):
         NotificationEmailReplyTo
     ).filter(
         NotificationEmailReplyTo.notification_id == notification_id
-    ).all()
+    ).first()
 
-    if len(email_reply_to) == 1:
-        return email_reply_to[0].email_address
+    if email_reply_to:
+        return email_reply_to.email_address

app/notifications/validators.py

@@ -140,5 +140,6 @@ def check_service_email_reply_to_id(service_id, reply_to_id):
         try:
             reply_to = dao_get_reply_to_by_id(service_id, reply_to_id)
         except NoResultFound:
-            message = 'email_reply_to_id does not exist in database'
+            message = 'email_reply_to_id {} does not exist in database for service id {}'\
+                .format(reply_to_id, service_id)
             raise BadRequestError(message=message)

app/v2/notifications/post_notifications.py

@@ -19,7 +19,9 @@ from app.notifications.process_notifications import (
     persist_notification,
     send_notification_to_queue,
     simulated_recipient,
-    persist_scheduled_notification, persist_email_reply_to_id_for_notification)
+    persist_scheduled_notification,
+    persist_email_reply_to_id_for_notification
+)
 from app.notifications.process_letter_notifications import (
     create_letter_notification
 )