code: private void writeTasks() throws IOException
     {
        writeAttributeTypes("task_types", TaskField.values());
  
        m_writer.writeStartList("tasks");
        for (Task task : m_projectFile.getChildTasks())
        {
           writeTask(task);
        }
        m_writer.writeEndList();
     }
docs: This method writes task data to a JSON file.
  Note that we write the task hierarchy in order to make rebuilding the hierarchy easier.