Danie-1

Make more node attributes public or add getter methods

1

I would like to use this library for rendering railroad diagrams for regular expressions. I would like to be able to use the current types to represent a railroad diagram,...

Fixes some README examples, and closes #13

If using python 3.10, 3.11, 3.12, 3.13 and so on, then checking `< "3.4"` gives the wrong result. I decided to also change the message because I found the message...