Minor code refactoring after PR review.

TNL-836

openassessment/xblock/openassessmentblock.py

@@ -224,7 +224,7 @@ class OpenAssessmentBlock(
         See also: submissions.api for details.
 
         Args:
-            anonymous_user_id(str):
+            anonymous_user_id(str): A unique anonymous_user_id for (user, course) pair.
         Returns:
             (dict): The student item associated with this XBlock instance. This
                 includes the student id, item id, and course id.

openassessment/xblock/staff_info_mixin.py

@@ -234,33 +234,36 @@ class StaffInfoMixin(object):
         submission_uuid = None
         submission = None
         assessment_steps = self.assessment_steps
+        anonymous_user_id = None
+        submissions = None
+        student_item = None
 
         if student_username:
             anonymous_user_id = self.get_anonymous_user_id(student_username, self.course_id)
             student_item = self.get_student_item_dict(anonymous_user_id=anonymous_user_id)
 
-            if anonymous_user_id:
-                # If there is a submission available for the requested student, present
-                # it. If not, there will be no other information to collect.
-                submissions = submission_api.get_submissions(student_item, 1)
-
-                if submissions:
-                    submission_uuid = submissions[0]['uuid']
-                    submission = submissions[0]
-
-                    if 'file_key' in submission.get('answer', {}):
-                        file_key = submission['answer']['file_key']
-
-                        try:
-                            submission['image_url'] = file_api.get_download_url(file_key)
-                        except file_api.FileUploadError:
-                            # Log the error, but do not prevent the rest of the student info
-                            # from being displayed.
-                            msg = (
-                                u"Could not retrieve image URL for staff debug page.  "
-                                u"The student username is '{student_username}', and the file key is {file_key}"
-                            ).format(student_username=student_username, file_key=file_key)
-                            logger.exception(msg)
+        if anonymous_user_id:
+            # If there is a submission available for the requested student, present
+            # it. If not, there will be no other information to collect.
+            submissions = submission_api.get_submissions(student_item, 1)
+
+        if submissions:
+            submission_uuid = submissions[0]['uuid']
+            submission = submissions[0]
+
+            if 'file_key' in submission.get('answer', {}):
+                file_key = submission['answer']['file_key']
+
+                try:
+                    submission['image_url'] = file_api.get_download_url(file_key)
+                except file_api.FileUploadError:
+                    # Log the error, but do not prevent the rest of the student info
+                    # from being displayed.
+                    msg = (
+                        u"Could not retrieve image URL for staff debug page.  "
+                        u"The student username is '{student_username}', and the file key is {file_key}"
+                    ).format(student_username=student_username, file_key=file_key)
+                    logger.exception(msg)
 
         example_based_assessment = None
         self_assessment = None