code: def get_score(student_item):
      
      try:
          student_item_model = StudentItem.objects.get(**student_item)
          score = ScoreSummary.objects.get(student_item=student_item_model).latest
      except (ScoreSummary.DoesNotExist, StudentItem.DoesNotExist):
          return None
  
      # By convention, scores are hidden if "points possible" is set to 0.
      # This can occur when an instructor has reset scores for a student.
      if score.is_hidden():
          return None
      else:
          return ScoreSerializer(score).data
docs: Get the score for a particular student item
  
      Each student item should have a unique score. This function will return the
      score if it is available. A score is only calculated for a student item if
      it has completed the workflow for a particular assessment module.
  
      Args:
          student_item (dict): The dictionary representation of a student item.
              Function returns the score related to this student item.
  
      Returns:
          score (dict): The score associated with this student item. None if there
              is no score found.
  
      Raises:
          SubmissionInternalError: Raised if a score cannot be retrieved because
              of an internal server error.
  
      Examples:
          >>> student_item = {
          >>>     "student_id":"Tim",
          >>>     "course_id":"TestCourse",
          >>>     "item_id":"u_67",
          >>>     "item_type":"openassessment"
          >>> }
          >>>
          >>> get_score(student_item)
          [{
              'student_item': 2,
              'submission': 2,
              'points_earned': 8,
              'points_possible': 20,
              'created_at': datetime.datetime(2014, 2, 7, 18, 30, 1, 807911, tzinfo=<UTC>)
          }]