please help me with the binary treefunction in ocaml

(* the type of a plymorphic tree *) type 'a tree = | Leaf of 'a | Node of 'a tree * 'a tree I e standard functions to convert between strin and char list -) let explodes let rec exp 1 l it is then I else exp (1 - 1) (s. [1] : 1) in exp (String. Length - 1) let implode let res - String.create (List. Length 1) in let ree imp 1 = function | 11 -> res IC :: 1 -> res. [1] (fool * (char List option) such that read_bool_prefix (explode "true???" = Some true, M:7: ***) read_bool_prefix (explode "false123" Sone (false, D'1: 2: 1301) read_bool_prefix (explode "antythingales") = None read_bool prefix = None write a helper function read_bool_tree_prefix (char list) -> ((bool tree (char list)) option) such that read_bool_tree_prefix 11 = None read bool_tree_prefix (explode "true???") - Sone (Leaf true, '?': 17:11 read_booltre prefix (explode "true false)124") = Sone (Node. (Leaf true, Leaf false), 1'1': '2":"41) read_bool_tree_prefix (explode "true"(true false)) aaa") = Some (Node (Leaf true, Node (Leat true, Leaf false)), 'a'; 'a'; 'a'1) read_bool_tree_prefix (explode "true"(true fa seana") - None