anchor.diff:  %%--------------------------------------------------------------------
   %% @doc All view privileges in OZ API.
   %%--------------------------------------------------------------------
  --spec oz_api_viewer() -> [oz_api_privilege()].
  -oz_api_viewer() -> [
  +-spec oz_viewer() -> [oz_privilege()].
  +oz_viewer() -> [
       list_users,
       list_users_of_provider,
       list_groups,
  
positive.code: 
  %% User privileges with regards to handle service.
  -type handle_service_privilege() ::
  %%register_handle_service | list_handle_services | % we may need those privileges for admins in oz_api_privileges
  delete_handle_service | modify_handle_service | view_handle_service |
  register_handle.
  
  
negative.code: %%--------------------------------------------------------------------
  %% @doc All OZ API privileges.
  %%--------------------------------------------------------------------
  -spec oz_privileges() -> [oz_privilege()].
  oz_privileges() ->
      ordsets:union(
          oz_viewer(),
          ordsets:from_list([
              view_privileges,
              set_privileges,
  