ABsoluteMaybe.Persistence.Xml.XmlExperimentCommands.GetOrCreateParticipationRecord C# (CSharp) Метод

        public ParticipationRecord GetOrCreateParticipationRecord(string experimentName,
		                                                          Func<string> chooseAnOptionForUser,
		                                                          string userId)
        {
            var xml = Load();

            var experiment = xml.Root.Elements("Experiment").Single(x => x.Attribute("Name").Value == experimentName);
            if (experiment.Element("Participants") == null)
                experiment.Add(new XElement("Participants"));

            var participants = experiment.Element("Participants");
            var existingRecord = participants.Elements("Participant").SingleOrDefault(x => x.Attribute("Id").Value == userId);
            if (existingRecord != null)
                return new ParticipationRecord(
                    existingRecord.Attribute("Id").Value,
                    existingRecord.Value,
                    existingRecord.Attribute("HasConverted") == null
                        ? false
                        : bool.Parse(existingRecord.Attribute("HasConverted").Value),
                    existingRecord.Attribute("DateConverted") == null
                        ? (DateTime?) null
                        : DateTime.Parse(existingRecord.Attribute("DateConverted").Value)
                    );

            var assignedOption = chooseAnOptionForUser();
            experiment.Element("Participants").Add(new XElement("Participant",
                                                                new XAttribute("Id", userId),
                                                                new XCData(assignedOption)));

            Save(xml);
            return new ParticipationRecord(userId, assignedOption, false, null);
        }