fix formatting

app/email_utils.py

@@ -209,4 +209,4 @@ def add_or_replace_header(msg: Message, header: str, value: str):
 
 def delete_header(msg: Message, header: str):
     if msg[header]:
-        del msg[header]
+        del msg[header]

email_handler.py

@@ -45,7 +45,9 @@ from app.email_utils import (
     send_email,
     add_dkim_signature,
     get_email_domain_part,
-    add_or_replace_header, delete_header)
+    add_or_replace_header,
+    delete_header,
+)
 from app.extensions import db
 from app.log import LOG
 from app.models import GenEmail, ForwardEmail, ForwardEmailLog, CustomDomain