public UserInfo GetUserByPhone(string phone)
        {
            UserInfo userInfo = Model.GetUser(phone);

            if (userInfo == null)
            {
                View.AppendNotifierText("Not found");
            }
            return(userInfo);
        }
        public IReadOnlyCollection <UserInfo> GetUserByName(string name, string surname)
        {
            IReadOnlyCollection <UserInfo> users = Model.GetUser(name, surname);

            if (users.Count == 0)
            {
                View.AppendNotifierText("Doesn't exist");
            }
            return(users);
        }