public IActionResult Post([FromBody] PhonesData value)
        {
            var validationResult = value.Validate();

            if (!validationResult.IsValid)
            {
                return(BadRequest(validationResult.Errors));
            }

            _memCache.Add(value);

            return(Ok($"{value.ToString()} был добавлен!"));
        }
        public IActionResult Put(Guid id, [FromBody] PhonesData value)
        {
            if (!_memCache.Has(id))
            {
                return(NotFound("No such"));
            }

            var validationResult = value.Validate();

            if (!validationResult.IsValid)
            {
                return(BadRequest(validationResult.Errors));
            }

            var previousValue = _memCache[id];

            _memCache[id] = value;

            return(Ok($"{previousValue.ToString()} обновлён до {value.ToString()}"));
        }