Small refactoring and adding comments in response to PR comments.

apps/openassessment/assessment/models.py

@@ -352,6 +352,8 @@ class Assessment(models.Model):
         if not assessments:
             return []
 
+        # Generate a cache key that represents all the assessments we're being
+        # asked to grab scores from (comma separated list of assessment IDs)
         cache_key = "assessments.scores_by_criterion.{}".format(
             ",".join(str(assessment.id) for assessment in assessments)
         )
@@ -394,6 +396,14 @@ class AssessmentPart(models.Model):
     def points_possible(self):
         return self.option.criterion.points_possible
 
+    @classmethod
+    def add_to_assessment(cls, assessment, option_ids):
+        """Creates AssessmentParts and adds them to `assessment`."""
+        cls.objects.bulk_create([
+            cls(assessment=assessment, option_id=option_id)
+            for option_id in option_ids
+        ])
+
 
 class AssessmentFeedback(models.Model):
     """A response to a submission's feedback, judging accuracy or helpfulness."""

apps/openassessment/assessment/peer_api.py

@@ -199,10 +199,7 @@ def create_assessment(
         # We do this to do a run around django-rest-framework serializer
         # validation, which would otherwise require two DB queries per
         # option to do validation. We already validated these options above.
-        AssessmentPart.objects.bulk_create([
-            AssessmentPart(assessment=assessment, option_id=option_id)
-            for option_id in option_ids
-        ])
+        AssessmentPart.add_to_assessment(assessment, option_ids)
 
         student_item = submission.student_item
         student_item_dict = StudentItemSerializer(student_item).data

apps/openassessment/assessment/self_api.py

@@ -94,10 +94,7 @@ def create_assessment(submission_uuid, user_id, options_selected, rubric_dict, s
     # We do this to do a run around django-rest-framework serializer
     # validation, which would otherwise require two DB queries per
     # option to do validation. We already validated these options above.
-    AssessmentPart.objects.bulk_create([
-        AssessmentPart(assessment=assessment, option_id=option_id)
-        for option_id in option_ids
-    ])
+    AssessmentPart.add_to_assessment(assessment, option_ids)
 
     # Return the serialized assessment
     return full_assessment_dict(assessment)