public void TestFactoryRegisterNull()
        {
            //Given
            IValueExpressionGenerator conv = null;

            //Then
            Assert.ThrowsAny <ArgumentNullException>(() => ValueExpressionGeneratorFactory.Register(conv));
        }
        public static void Register(IValueExpressionGenerator converter)
        {
            if (converter == null)
            {
                throw new ArgumentNullException(nameof(converter));
            }

            _converters[converter.GeneratingType] = converter;
        }