anchor.diff:      ordsets:union(
           handle_user(),
           ordsets:from_list([
  -            register_handle,
               list_handles,
               delete_handle,
               modify_handle,
  
positive.code: 
  %% User privileges with regards to handle service.
  -type handle_service_privilege() :: register_handle_service |
  list_handle_services | delete_handle_service | modify_handle_service |
  view_handle_service.
  
  %% User privileges with regards to handle.
  -type handle_privilege() :: register_handle | list_handles | delete_handle |
  modify_handle | view_handle.
  
  %%%===================================================================
  %%% API
  
negative.code:         handle_service_user(),
          ordsets:from_list([
              register_handle_service,
              delete_handle_service,
              modify_handle_service,
              view_handle_service
  