public static string ImportProjects(TeisterMaskContext context, string xmlString)
        {
            var xmlSerializer = new XmlSerializer(typeof(ImportProjectsDtoXml[]), new XmlRootAttribute("Projects"));
            var projectsDto = (ImportProjectsDtoXml[])xmlSerializer.Deserialize(new StringReader(xmlString));

            var sb = new StringBuilder();
            var projects = new List<Project>();

            foreach (var projectDto in projectsDto)
            {
                if (!IsValid(projectDto))
                {
                    sb.AppendLine($"{ErrorMessage}");
                    continue;
                }

                var tasks = new List<Task>();

                var projectOpenDate = DateTime.ParseExact(projectDto.OpenDate, "dd/MM/yyyy", CultureInfo.InvariantCulture);

                var projectDueDate = projectDto.DueDate == null || projectDto.DueDate == "" ? (DateTime?)null : DateTime.ParseExact(projectDto.DueDate, @"dd/MM/yyyy", CultureInfo.InvariantCulture);
                foreach (var task in projectDto.ProjectTasks)
                {

                    if (!IsValid(task))
                    {
                        sb.AppendLine($"{ErrorMessage}");
                        continue;
                    }

                    var taskOpenDate = DateTime.ParseExact(task.OpenDate, "dd/MM/yyyy", CultureInfo.InvariantCulture);
                    var taskDueDate = DateTime.ParseExact(task.DueDate, "dd/MM/yyyy", CultureInfo.InvariantCulture);

                    //var correctDate = true;

                    //•   task open date is before project open date or task due date is after project due date)

                    if (taskOpenDate < projectOpenDate || taskDueDate > projectDueDate)
                    {
                        sb.AppendLine($"{ErrorMessage}");
                        continue;
                    }

                    tasks.Add(new Task()
                    {
                        Name = task.Name,
                        OpenDate = DateTime.ParseExact(task.OpenDate, "dd/MM/yyyy", CultureInfo.InvariantCulture),
                        DueDate = DateTime.ParseExact(task.DueDate, "dd/MM/yyyy", CultureInfo.InvariantCulture),
                        ExecutionType = Enum.Parse<ExecutionType>(task.ExecutionType),
                        LabelType = Enum.Parse<LabelType>(task.LabelType)

                    });
                }

                var project = new Project
                {
                    Name = projectDto.Name,
                    OpenDate = projectOpenDate,
                    DueDate = projectDueDate,
                    Tasks = tasks
                };


                projects.Add(project);
                sb.AppendLine($"Successfully imported project - {project.Name} with {project.Tasks.Count} tasks.");
            }


            context.Projects.AddRange(projects);
            context.SaveChanges();
            return sb.ToString().TrimEnd();
        }