new_contents: # -*- coding: utf-8 -*-
  from south.v2 import DataMigration
  from education.models import Response
  
  
  class Migration(DataMigration):
  
      def forwards(self, orm):
          implausibles = Response.objects.filter(has_errors=False,
                                                 message__direction='I',
                                                 eav_values__value_float__gt=5000) \
                                         .update(has_errors=True)
  
  
      def backwards(self, orm):
          originals = Response.objects.filter(has_errors = True,
                                              message__direction='I',
                                              eav_values__value_float__gt = 5000) \
                                      .update(has_errors=False)
  
subject: Mark all implausibly large responses as having errors.