module main

pub struct Tree {}

pub fn (tree &Tree) str() string {
	return ''
}

pub struct TreeTwo {
	Tree
}

pub fn TreeTwo.from_string(tree_string string) !&TreeTwo {
	return &TreeTwo{}
}

fn main() {
	tree := TreeTwo.from_string('') or { panic(err) }
	println(tree.str())
}