new_contents: # -*- coding: utf-8 -*-
  from __future__ import unicode_literals
  
  from django.db import migrations
  
  
  def clear_old_results(apps, schema_editor):
      Scenario = apps.get_model('modeling', 'Scenario')
  
      Scenario.objects.all().update(
          results='[]',
          modification_hash='',
          inputmod_hash='',
      )
  
  
  class Migration(migrations.Migration):
  
      dependencies = [
          ('modeling', '0020_auto_20161206_1556'),
      ]
  
      operations = [
          migrations.RunPython(clear_old_results)
      ]
  
subject: Clear old Pollination Mapper results