Adding migration to store purchased mode in PaidCourseRegistration

common/djangoapps/course_modes/models.py

@@ -33,6 +33,7 @@ class CourseMode(models.Model):
     currency = models.CharField(default="usd", max_length=8)
 
     DEFAULT_MODE = Mode('honor', _('Honor Code Certificate'), 0, '', 'usd')
+    DEFAULT_MODE_SLUG = 'honor'
 
     class Meta:
         """ meta attributes of this model """

common/djangoapps/student/models.py

@@ -827,9 +827,6 @@ class CourseEnrollment(models.Model):
     @classmethod
     def is_enrolled(cls, user, course_id):
         """
-        Remove the user from a given course. If the relevant `CourseEnrollment`
-        object doesn't exist, we log an error but don't throw an exception.
-
         Returns True if the user is enrolled in the course (the entry must exist
         and it must have `is_active=True`). Otherwise, returns False.