code: def migrate(ctx, start_version, end_version):
      
      if ctx.type == 'file':
          if ctx.data_file:
              file_path = ctx.data_file
          else:
              file_path = os.path.join(ctx.data_file, ctx.namespace + '.json')
  
          # todo make this more like alemebic and determine/load versions automatically
          with open(file_path, 'r') as f:
              data = json.loads(f.read())
  
          data = run_migration(data, start_version, end_version)
          with open(file_path, 'w') as f:
              f.write(json.dumps(data))
docs: Transition from one SWAG schema to another.