diff --git a/courses/tasks.py b/courses/tasks.py
index 9384958..7477419 100644
--- a/courses/tasks.py
+++ b/courses/tasks.py
@@ -2,12 +2,12 @@ from progress.models import ProgressLesson, Progress
 from django.contrib.auth import get_user_model
 
 
-def add_lesson(user_out_key: str, course_token: str, lesson_token: str, teacher_key: str, is_hm: bool):
+def add_lesson(user_out_key: str, course_token: str, lesson_token: str, is_hm: bool):
 
     p = Progress.objects.get(course_token=course_token, user__out_key=user_out_key)
 
     ProgressLesson.objects.get_or_create(
         progress=p,
         lesson_token=lesson_token,
-        checker=get_user_model().objects.get(out_key=(teacher_key if is_hm else user_out_key)),
+        checker=get_user_model().objects.get(out_key=(p.teacher.out_key if is_hm else user_out_key)),
     )
\ No newline at end of file
diff --git a/courses/views.py b/courses/views.py
index 0964098..ee75638 100644
--- a/courses/views.py
+++ b/courses/views.py
@@ -258,6 +258,6 @@ class LessonDetail(APIView):
             return Response("Permission denied", status=403)
 
         # TODO Задача для селери
-        add_lesson(request.user.out_key, course.token, lesson.token, course.get_teacher(), lesson.is_hm)
+        add_lesson(request.user.out_key, course.token, lesson.token, lesson.is_hm)
 
         return Response(l, status=200)
diff --git a/finance/migrations/0011_auto_20180507_1412.py b/finance/migrations/0011_auto_20180507_1412.py
new file mode 100644
index 0000000..e11255a
--- /dev/null
+++ b/finance/migrations/0011_auto_20180507_1412.py
@@ -0,0 +1,22 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.6 on 2018-05-07 14:12
+from __future__ import unicode_literals
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('finance', '0010_auto_20180412_1628'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='bill',
+            name='opener',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, to=settings.AUTH_USER_MODEL, verbose_name='Ответственный сотрудник'),
+        ),
+    ]
diff --git a/finance/models.py b/finance/models.py
index e824ea3..2edf8fe 100755
--- a/finance/models.py
+++ b/finance/models.py
@@ -17,7 +17,9 @@ logger_business_rules = logging.getLogger('business_rules')
 class Bill(models.Model):
     course_token = models.UUIDField(verbose_name="Токен курса", editable=False)
     user = models.ForeignKey(settings.AUTH_USER_MODEL, verbose_name='Плательщик', related_name='bill_user')
-    opener = models.ForeignKey(settings.AUTH_USER_MODEL, verbose_name='Ответственный сотрудник', null=True)
+    opener = models.ForeignKey(
+        settings.AUTH_USER_MODEL, verbose_name='Ответственный сотрудник', null=True, blank=True,
+        on_delete=models.SET_NULL)
     comment = models.TextField(verbose_name='Комментарий продавца', help_text='Будет показано пользователю',
                                blank=True, editable=False)
     description = models.TextField(verbose_name='Внутренняя заметка', blank=True)
diff --git a/finance/views.py b/finance/views.py
index 9b7cc6c..780114e 100644
--- a/finance/views.py
+++ b/finance/views.py
@@ -143,8 +143,6 @@ class InvoiceDetailView(APIView):
             key = request.JSON.get('key', None)
             pay_count = int(request.JSON.get('pay_count', '1'))
 
-            print(key)
-
             if bill_id is None:
                 return Response("Не передан id счёта", status=400)
 
diff --git a/progress/migrations/0014_auto_20180507_1412.py b/progress/migrations/0014_auto_20180507_1412.py
new file mode 100644
index 0000000..07cf083
--- /dev/null
+++ b/progress/migrations/0014_auto_20180507_1412.py
@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.6 on 2018-05-07 14:12
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('progress', '0013_progresslesson_dif_check_timestamps'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='progresslesson',
+            name='last_update',
+            field=models.DateTimeField(auto_now_add=True, verbose_name='Дата последней сдачи'),
+        ),
+    ]