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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 sync_week_metric(self, unique_identifier, metric, start_date, end_date):
 """ Uses the count for each day in the date range to recalculate the counters for the weeks for the ``metric`` for ``unique_identifier``. Useful for updating the counters for week and month after using set_metric_by_day. The redis backend supports lists for both ``unique_identifier`` and ``metric`` allowing for the setting of multiple metrics for multiple unique_identifiers efficiently. Not all backends may support this. :param unique_identifier: Unique string indetifying the object this metric is for :param metric: A unique name for the metric you want to track :param start_date: Date syncing starts :param end_date: Date syncing end """

        metric = [metric] if isinstance(metric, basestring) else metric
        unique_identifier = [unique_identifier] if not isinstance(unique_identifier, (types.ListType, types.TupleType, types.GeneratorType,)) else unique_identifier
        closest_monday_from_date = self._get_closest_week(start_date)
        num_weeks = self._num_weeks(start_date, end_date)
        metric_key_date_range = self._get_weekly_date_range(closest_monday_from_date, datetime.timedelta(weeks=num_weeks))

        week_date_generator = (closest_monday_from_date + datetime.timedelta(days=i) for i in itertools.count(step=7))
        #generate a list of mondays in between the start date and the end date
        weeks_to_update = list(itertools.islice(week_date_generator, num_weeks))
        for uid in unique_identifier:
            for single_metric in metric:
                for week in weeks_to_update:
                    _, series_results = self.get_metric_by_day(uid, single_metric, from_date=week, limit=7)
                    week_counter = sum([value for key, value in series_results.items()])

                    hash_key_weekly = self._get_weekly_metric_key(uid, week)
                    weekly_metric_name = self._get_weekly_metric_name(single_metric, week)
                    with self._analytics_backend.map() as conn:
                        conn.hset(hash_key_weekly, weekly_metric_name, week_counter)