[IMP] mail: remove unused imports

addons/mail/models/mail_activity.py

@@ -5,8 +5,6 @@ from datetime import date, datetime, timedelta
 import pytz
 
 from odoo import api, exceptions, fields, models, _
-from odoo.osv import expression
-from odoo.tools import pycompat
 
 
 class MailActivityType(models.Model):

addons/test_mail/tests/common.py

@@ -1,5 +1,4 @@
 # -*- coding: utf-8 -*-
-from json import dumps, loads
 
 import json