Enhance code structure

app/users/settings/forms.py

@@ -1,4 +1,3 @@
-from flask_login import current_user
 from flask_wtf import FlaskForm
 from flask_wtf.file import FileField, FileRequired
 from wtforms import (
@@ -17,7 +16,7 @@ from wtforms.validators import (
     Regexp
 )
 from app.models import User, UserSettingJobStatusMailNotificationLevel
-from app.wtforms.validators import FileSize
+from app.extensions.wtforms.validators import FileSize
 
 
 class UpdateAccountInformationForm(FlaskForm):