def test__str__(test_tree: Tree):
assert test_tree.__str__() == test_tree.to_string_tree()
def test_to_string_tree(test_tree: Tree):
assert test_tree.to_string_tree() == "root(0)[child1(1)[child1_child1(11)[]], " \
"child2(2)[child2_child1(21)[], child2_child2(22)[]], " \
"child3(3)[child3_child1(31)[], child3_child2(32)[], " \
"child3_child3(33)[child3_child3_child1(331)[]]]]"