old_contents: from django.core.management.base import BaseCommand, CommandError
  from msgvis.apps.importer.models import create_an_instance_from_json
  
  from msgvis.apps.corpus.models import Dataset
  
  
  class Command(BaseCommand):
      """
      Import a corpus of message data into the database.
  
      .. code-block :: bash
  
          $ python manage.py import_corpus <file_path>
  
      """
      args = '<corpus_filename>'
      help = "Import a corpus into the database."
  
      def handle(self, corpus_filename, *args, **options):
          if not corpus_filename:
              raise CommandError('Corpus filename must be provided.')
  
          fp = open(corpus_filename, 'r')
          dataset_obj = Dataset.objects.create(name=corpus_filename, description=corpus_filename)
  
          for json_str in iter(lambda: fp.readline(), ''):
              json_str = json_str.rstrip('\r\n')
              if len(json_str) > 0:
                  create_an_instance_from_json(json_str, dataset_obj)
  
new_contents: from django.core.management.base import BaseCommand, CommandError
  from msgvis.apps.importer.models import create_an_instance_from_json
  from optparse import make_option
  
  from msgvis.apps.corpus.models import Dataset
  
  
  class Command(BaseCommand):
      """
      Import a corpus of message data into the database.
  
      .. code-block :: bash
  
          $ python manage.py import_corpus <file_path>
  
      """
      args = '<corpus_filename>'
      help = "Import a corpus into the database."
      option_list = BaseCommand.option_list + (
                          make_option('-d', '--dataset',
                              action='store',
                              dest='dataset',
                              default=False,
                              help='Set a target dataset to add to'),
                          )
  
      def handle(self, corpus_filename, *args, **options):
  
          if not corpus_filename:
              raise CommandError('Corpus filename must be provided.')
  
          dataset = options.get('dataset')
  
          fp = open(corpus_filename, 'r')
          if dataset is None:
              dataset_obj = Dataset.objects.create(name=corpus_filename, description=corpus_filename)
          else:
              dataset_obj, created = Dataset.objects.get_or_create(name=dataset, description=dataset)
  
          for json_str in iter(lambda: fp.readline(), ''):
              json_str = json_str.rstrip('\r\n')
              if len(json_str) > 0:
                  create_an_instance_from_json(json_str, dataset_obj)
  
subject: modify the importing command to allow specifying the target dataset