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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 ImportStations(self, station_file, adv_file):
    "Imports the rec_ort.mdv file."
    for id, name, x, y, uic_code in  \
    ReadCSV(station_file, ['ORT_NR', 'ORT_NAME',
                'ORT_POS_X', 'ORT_POS_Y', 'ORT_NR_NATIONAL']):
      station = Station()
      station.id = id
      station.position = self.coord_converter(float(x), float(y))
      station.uic_code = ''
      if uic_code and len(uic_code) == 7 and uic_code[:2] == '85':
        station.uic_code = uic_code
      station.name, station.city = self.DemangleName(name)
      station.country = 'CH'
      station.url = 'http://fahrplan.zvv.ch/?to.0=' + \
                    urllib.quote(name.encode('iso-8859-1'))
      station.advertised_lines = set()
      self.stations[id] = station
    for station_id, line_id in ReadCSV(adv_file, ['ORT_NR', 'LI_NR']):
      if station_id in self.stations:
        # Line ids in this file have leading zeroes, remove.
        self.stations[station_id].advertised_lines.add(line_id.lstrip("0"))
      else:
        print("Warning, advertised lines file references " \
              "unknown station, id " + station_id)