anchor.diff:  operation_supported(get, configuration, _) -> true;
   
   operation_supported(_, _, _) -> false.
  +
  +
  +%%--------------------------------------------------------------------
  +%% @doc
  +%% Determines if given {Aspect, Scope} pair is subscribable, i.e. clients can
  +%% subscribe to receive updates concerning the aspect of entity.
  +%% @end
  +%%--------------------------------------------------------------------
  +-spec is_subscribable(entity_logic:aspect(), entity_logic:scope()) ->
  +    boolean().
  +is_subscribable(_, _) -> false.
   
   
   %%--------------------------------------------------------------------
  
positive.code: 
  %%--------------------------------------------------------------------
  %% @doc
  %% Returns validity verificators for given request.
  %% Returns a map with 'required', 'optional' and 'at_least_one' keys.
  %% Under each of them, there is a map:
  
negative.code: -include_lib("ctool/include/privileges.hrl").
  -include_lib("ctool/include/api_errors.hrl").
  
  -export([fetch_entity/1, operation_supported/3, is_subscribable/2]).
  -export([create/1, get/2, update/1, delete/1]).
  -export([exists/2, authorize/2, required_admin_privileges/1, validate/1]).
  
  %%%===================================================================
  %%% API
  