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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 clean(self):
 """Clean queue items from a previous session. In case a previous session crashed and there are still some running entries in the queue ('running', 'stopping', 'killing'), we clean those and enqueue them again. """

        for _, item in self.queue.items():
            if item['status'] in ['paused', 'running', 'stopping', 'killing']:
                item['status'] = 'queued'
                item['start'] = ''
                item['end'] = ''