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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 fetch(self, minutes=values.unset, start_date=values.unset, end_date=values.unset, task_channel=values.unset):
 """ Fetch a WorkerStatisticsInstance :param unicode minutes: Filter cumulative statistics by up to 'x' minutes in the past. :param datetime start_date: Filter cumulative statistics by a start date. :param datetime end_date: Filter cumulative statistics by a end date. :param unicode task_channel: Filter cumulative statistics by TaskChannel. :returns: Fetched WorkerStatisticsInstance :rtype: twilio.rest.taskrouter.v1.workspace.worker.worker_statistics.WorkerStatisticsInstance """

        return self._proxy.fetch(
            minutes=minutes,
            start_date=start_date,
            end_date=end_date,
            task_channel=task_channel,
        )