public Response GetAllUsers()
        {
            Response retval;

            try
            {
                var DsUsers = _dal.GetAllUsers();
                if (DsUsers.Tables[0].Rows.Count > 0)
                {
                    var listResult = convertDataToUsersList(DsUsers);
                    retval = new GetAllUsersResponseOk(listResult);
                }
                else
                {
                    retval = new GetAllUsersResponseError("There are no users to present");
                }
            }
            catch
            {
                retval = new AppResponseError("Error, can't fetch users");
            }
            return(retval);
        }