Add docs/code comments for message-send-flow

app/delivery/send_to_providers.py

@@ -22,11 +22,11 @@ from app.serialised_models import SerialisedService, SerialisedTemplate
 
 
 def send_sms_to_provider(notification):
-    '''
+    """
     This is the last step in the message send flow.
     We get necessary data for recipient, template,
     notification and send it off to the provider.
-    '''
+    """
     # we no longer store the personalisation in the db,
     # need to retrieve from s3 before generating content
     # However, we are still sending the initial verify code through personalisation