val tf1 : string -> int
val tf2: ‘a -> ‘b -> ‘b -> bool
val tf3: ‘a list -> ‘a list -> ‘a
val concat : string -> string -> string
val add_to_float : int -> float -> float
val fib : int -> int
val add_three : int list -> int list
val filter : ‘a -> ‘a list -> ‘a list
val double : ‘a list -> ‘a list