Add typehints to email code

app/email.py

@@ -1,25 +1,32 @@
-from flask import current_app, render_template
+from flask import current_app, Flask, render_template
 from flask_mail import Message
 from threading import Thread
 from app import mail
 
 
-def create_message(recipient, subject, template, **kwargs):
+def create_message(
-    subject_prefix: str = current_app.config['NOPAQUE_MAIL_SUBJECT_PREFIX']
+    recipient: str,
-    msg: Message = Message(
+    subject: str,
-        body=render_template(f'{template}.txt.j2', **kwargs),
+    template: str,
-        html=render_template(f'{template}.html.j2', **kwargs),
+    **context
+) -> Message:
+    message = Message(
+        body=render_template(f'{template}.txt.j2', **context),
+        html=render_template(f'{template}.html.j2', **context),
         recipients=[recipient],
-        subject=f'{subject_prefix} {subject}'
+        subject=f'[nopaque] {subject}'
     )
-    return msg
+    return message
 
 
-def send(msg, *args, **kwargs):
+def send(message: Message) -> Thread:
-    def _send(app, msg):
+    def _send(app: Flask, message: Message):
         with app.app_context():
-            mail.send(msg)
+            mail.send(message)
 
-    thread = Thread(target=_send, args=[current_app._get_current_object(), msg])
+    thread = Thread(
+        target=_send,
+        args=[current_app._get_current_object(), message]
+    )
     thread.start()
     return thread