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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_top_submissions(course_id, item_id, item_type, number_of_top_scores, use_cache=True, read_replica=True):
 """Get a number of top scores for an assessment based on a particular student item This function will return top scores for the piece of assessment. It will consider only the latest and greater than 0 score for a piece of assessment. A score is only calculated for a student item if it has completed the workflow for a particular assessment module. In general, users of top submissions can tolerate some latency in the search results, so by default this call uses a cache and the read replica (if available). Args: course_id (str):
 The course to retrieve for the top scores item_id (str):
 The item within the course to retrieve for the top scores item_type (str):
 The type of item to retrieve number_of_top_scores (int):
 The number of scores to return, greater than 0 and no more than 100. Kwargs: use_cache (bool):
 If true, check the cache before retrieving querying the database. read_replica (bool):
 If true, attempt to use the read replica database. If no read replica is available, use the default database. Returns: topscores (dict):
 The top scores for the assessment for the student item. An empty array if there are no scores or all scores are 0. Raises: SubmissionNotFoundError: Raised when a submission cannot be found for the associated student item. SubmissionRequestError: Raised when the number of top scores is higher than the MAX_TOP_SUBMISSIONS constant. Examples: [{ 'score': 20, 'content': "Platypus" },{ 'score': 16, 'content': "Frog" }] """

    if number_of_top_scores < 1 or number_of_top_scores > MAX_TOP_SUBMISSIONS:
        error_msg = (
            u"Number of top scores must be a number between 1 and {}.".format(MAX_TOP_SUBMISSIONS)
        )
        logger.exception(error_msg)
        raise SubmissionRequestError(msg=error_msg)

    # First check the cache (unless caching is disabled)
    cache_key = "submissions.top_submissions.{course}.{item}.{type}.{number}".format(
        course=course_id,
        item=item_id,
        type=item_type,
        number=number_of_top_scores
    )
    top_submissions = cache.get(cache_key) if use_cache else None

    # If we can't find it in the cache (or caching is disabled), check the database
    # By default, prefer the read-replica.
    if top_submissions is None:
        try:
            query = ScoreSummary.objects.filter(
                student_item__course_id=course_id,
                student_item__item_id=item_id,
                student_item__item_type=item_type,
                latest__points_earned__gt=0
            ).select_related('latest', 'latest__submission').order_by("-latest__points_earned")

            if read_replica:
                query = _use_read_replica(query)
            score_summaries = query[:number_of_top_scores]
        except DatabaseError:
            msg = u"Could not fetch top score summaries for course {}, item {} of type {}".format(
                course_id, item_id, item_type
            )
            logger.exception(msg)
            raise SubmissionInternalError(msg)

        # Retrieve the submission content for each top score
        top_submissions = [
            {
                "score": score_summary.latest.points_earned,
                "content": SubmissionSerializer(score_summary.latest.submission).data['answer']
            }
            for score_summary in score_summaries
        ]

        # Always store the retrieved list in the cache
        cache.set(cache_key, top_submissions, TOP_SUBMISSIONS_CACHE_TIMEOUT)

    return top_submissions