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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 _set_winning_team(self):
 """Mark the winning team."""

        if not self._summary['finished']:
            return
        for team in self._summary['diplomacy']['teams']:
            team['winner'] = False
            for player_number in team['player_numbers']:
                for player in self._summary['players']:
                    if player_number == player['number']:
                        if player['winner']:
                            team['winner'] = True