let lst_subs_dbg (subs : t_subst list) (size : string) : ((Types_unify.term * Types_unify.term) list list) =
let rec help cnt str = function
| sub::subs -> help (cnt+1) ((lst_sub_dbg sub)::str) subs
| [] -> str
in
if subs = [] then [] else help 1 [] subs