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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 _update_stat(self, submission_type, increase_success, increase_fail):
 """Common method to update submission statistics."""

    stat = self.stats.get(submission_type, (0, 0))
    stat = (stat[0] + increase_success, stat[1] + increase_fail)
    self.stats[submission_type] = stat