public async Task <ITypeParserResult <T?> > ParseAsync(string value, IParameter parameter, CommandContext context)
{
if (string.IsNullOrWhiteSpace(value))
{
return(new NullableTypeParserResult <T>());
}
else
{
var result = await _nonNullableTypeParser.ParseAsync(value, parameter, context);
return(NullableTypeParserResult <T> .FromResult(result));
}
}