anchor.diff:    {stop, Reason :: term(), NewState :: #state{}}).
   handle_call({get}, _From, State) ->
     do_get_permissions(State);
  +handle_call({get, UserId, DeviceId}, _From, State) ->
  +  do_get_permission(State, UserId, DeviceId);
   handle_call({get, Id}, _From, State) when is_integer(Id) ->
     do_get_permissions_by_user_id(State, Id);
   handle_call({create, Permission}, _From, State) ->
  
positive.code: 
  -export([
    get/0,
    get_by_user_id/1,
    create/1,
    delete/1
  
negative.code: -spec(get() -> {ok, [Rec :: #permission{}]} | {error, string()}).
  get() ->
    gen_server:call(?SERVER, {get}).
  
  -spec(get(UserId :: integer(), DeviceId :: integer()) -> {ok, [Rec :: #permission{}]} | {error, string()}).
  get(UserId, DeviceId) ->
    gen_server:call(?SERVER, {get, UserId, DeviceId}).
  
  -spec(get_by_user_id(Id :: integer()) -> {ok, [Rec :: #permission{}]} | {error, string()}).
  get_by_user_id(Id) ->
  