Writing XML

public void WriteCostEstablishmentReport(FileInfo destination, EvaluationReport report)
{
    if (null == report)
    {
        throw new ArgumentNullException("report");
    }

    if (null == destination)
    {
        throw new ArgumentNullException("destination");
    }

    var tree =
        new XElement("FD_State_Cadastral_Valuation", MakeDataFundSchemaVersionAttribute(),
            GenerateReportHeader(report),
            new XElement("Package",
                GenerateGroupsList(report),
                new XElement("Evaluative_Factors", GenerateEvaluativeFactors(report)),
                new XElement("Appraise",
                    new XElement("Valuation",
                        from estates in report.CostEstablishment select new XElement("Group_Real_Estate_Valuation",
                            new XElement("Rationale", report.DivisionGroups[estates.Key].Rationale),
                                new XElement("Real_Estates",
                                    from realEstate in estates select
                                        GenerateEvaluatedRealEstate(realEstate.RealEstate, realEstate.GroupId))  )))));

            tree.Save(destination.ToString(), SaveOptions.None);
}