module Tree:sig..end
type t = |
 
T of string * t list
 (* A tree of messages. The tree (msg,sub_msgs) is interpreted as meaning that sub_msgs are the various possible explanations for msg. *)
val leaf  : string -> t val add_child  : t -> t -> t add_child t x inserts x as the right-most child of t.val to_string  : t -> string