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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 add_station(self, mv_station, force=False):
 """Adds MV station if not already existing Args ---- mv_station: MVStationDing0 Description #TODO force: bool If True, MV Station is set even though it's not empty (override) """

        if not isinstance(mv_station, MVStationDing0):
            raise Exception('Given MV station is not a MVStationDing0 object.')
        if self._station is None:
            self._station = mv_station
            self.graph_add_node(mv_station)
        else:
            if force:
                self._station = mv_station
            else:
                raise Exception('MV Station already set, use argument `force=True` to override.')