Report None for individual student's scaled score when there is no score

analyze_grades.py

@@ -134,7 +134,7 @@ def print_sample_scores(assignment: CanvasAssignment,
         i = 1
         for student in selected_students:
             print(f'Student {i:>2} -- raw score: {scores[student]}'
-                  f'\tscaled score: {100 * scores[student] / points_possible}')
+                  f'\tscaled score: {100 * scores[student] / points_possible if scores[student] is not None else None}')
             i += 1
         print('Collect sample materials --')
         print(f'"A" student: {a_student.get_name() if a_student is not None else a_student}')