> You can not use the same implementation of the visitor for Num, Str, NameConstant and Ellipsis, because all these classes use different attribute for saving the value

ah yes, this is true -- maybe the better change would be to just add `@property value` to each of those instead of collapsing the classes? (If that's the actual convenience we're trying to achieve)

> No need to call generic_visit() from visit_Constant() -- Constant nodes should not contain AST nodes.

correct there's no need, but it's a best practice to always call `generic_visit` in all `visit_*` methods, I have a linter I haven't finished up yet that checks this.  And who knows if that'll be true in the future!