add import de tradução

sapl/base/receivers.py

@@ -9,6 +9,7 @@ from django.db.models.signals import post_delete, post_save,\
 from django.db.utils import DEFAULT_DB_ALIAS
 from django.dispatch import receiver
 from django.utils import timezone
+from django.utils.translation import ugettext_lazy as _
 
 from sapl.base.email_utils import do_envia_email_tramitacao
 from sapl.base.models import AuditLog, TipoAutor, Autor