Change the structure of the tree object
Give better name to variables
Improve code
Optimization
Simplify code
Use boolean switches for import/export modes
Simplify comment
Fix docstring
The current section is not an ancestor
Add _get_descendants
Do not inherit options by default
Expand docstring
Swap the indices of options' and subsections' dictionaries in a Section object
Fix importing algorithm
Reimplement exporting to file
Add reminders to TODO