old_contents: from data_collection.management.commands import BaseHalaroseCsvImporter
  
  class Command(BaseHalaroseCsvImporter):
      council_id      = 'E08000019'
      addresses_name  = 'local.2018-05-03/Version 1/polling_station_export-2018-03-16.csv'
      stations_name   = 'local.2018-05-03/Version 1/polling_station_export-2018-03-16.csv'
      elections       = ['local.2018-05-03']
      csv_encoding    = 'windows-1252'
  
new_contents: import os
  from django.contrib.gis.geos import Point
  from data_collection.management.commands import BaseHalaroseCsvImporter
  from pollingstations.models import PollingStation
  
  class Command(BaseHalaroseCsvImporter):
      council_id      = 'E08000019'
      addresses_name  = 'local.2018-05-03/Version 1/polling_station_export-2018-03-16.csv'
      stations_name   = 'local.2018-05-03/Version 1/polling_station_export-2018-03-16.csv'
      elections       = ['local.2018-05-03']
      csv_encoding    = 'windows-1252'
  
      def get_station_hash(self, record):
          return "-".join([
              record.pollingstationnumber.strip(),
          ])
  
      def address_record_to_dict(self, record):
          if record.houseid == '12006669':
              return None
          return super().address_record_to_dict(record)
  
      # Sheffield have supplied an additional file with
      # better grid references for the polling stations
      def post_import(self):
          filepath = os.path.join(
              self.base_folder_path,
              'local.2018-05-03/Version 1/Polling_Stations with GIS coordinate Sheffield.csv'
          )
          gridrefs = self.get_data('csv', filepath)
  
          print("Updating grid refs...")
          for record in gridrefs:
              stations = PollingStation.objects.filter(
                  council_id=self.council_id,
                  internal_council_id=self.get_station_hash(record)
              )
              if len(stations) == 1:
                  station = stations[0]
                  station.location = Point(
                      float(record.easting),
                      float(record.northing),
                      srid=27700
                  )
                  self.check_station_point({
                      'location': station.location,
                      'council_id': station.council_id,
                  })
                  station.save()
              else:
                  print("Could not find station id " + self.get_station_hash(record))
          print("...done")
  
subject: use polling station co-ordinates supplied by Sheffield (closes #1220)