public IndexConfiguration HasIndex <TIndex>(Expression <Func <TEntityType, TIndex> > indexExpression)
        {
            Check.NotNull(indexExpression, "indexExpression");


            var indexProperties = indexExpression.GetSimplePropertyAccessList().Select(p => p.Single());

            return(new IndexConfiguration(
                       _entityTypeConfiguration.Index(new PropertyPath(indexProperties))));
        }