pub fn clear(tree: Tree(a, b)) -> Tree(a, b)

pub fn delete(tree: Tree(a, b), key: a) -> Tree(a, b)

pub fn draw(
  tree: Tree(a, b),
  to_string: fn(a, b) -> String,
) -> String

pub fn find(tree: Tree(a, b), key: a) -> Result(#(a, b), Nil)

pub fn fold(tree: Tree(a, b), acc: c, fun: fn(c, a, b) -> c) -> c

pub fn foldr(
  tree: Tree(a, b),
  acc: c,
  fun: fn(c, a, b) -> c,
) -> c

pub fn insert(tree: Tree(a, b), key: a, value: b) -> Tree(a, b)

pub fn new(compare: fn(a, a) -> Order) -> Tree(a, b)