old_contents: 
  from bundles import Environment, Assets, Bundle, Manifest
  import filters as f
  from options import Option, Options, Undefined, dict_getter
  
  
new_contents: 
  from bundles import Environment, Assets, Bundle, Manifest
  import filters as f
  from options import Option, Options, Undefined, dict_getter
  from pipeable import worker
  
  
subject: Make @worker available for import on ass.ets.