code: def db_downgrade(version):
      
      v1 = get_db_version()
      migrate_api.downgrade(url=db_url, repository=db_repo, version=version)
      v2 = get_db_version()
  
      if v1 == v2:
          print 'No changes made.'
      else:
          print 'Downgraded: %s ... %s' % (v1, v2)
docs: Downgrade the database