private Action <TSource, TSource> GetCopyPk(IContextAdapter contextAdapter)
{
var path = ExpressHelper.GetPath(_extractor);
var propertyName = contextAdapter.GetBackwardKeyProperty <TSource>(path);
var expression = ExpressHelper.CreateCopy <TSource, TSource>(
$"{path}.{contextAdapter.GetPk<TSource>().PropertyName}", propertyName);
return(expression.Compile());
}
