public async Task <OperationalResult <bool> > IsExist(Operational <UserQueryModel> operational, CancellationToken cancellationToken = default) { var queryModel = operational.Parameter; Expression <Func <User, bool> > expression = p => p.No == queryModel.UserNo; var count = await _userStore.CountAsync(expression, cancellationToken); return(OperationalResult <bool> .Ok(count > 0)); }