find_consts_thy : string list -> hol_type -> term list
> find_consts_thy ["bool"] ``:'a -> 'a set -> bool``; val it = [“$IN”]: term list
   > find_consts_thy ["arithmetic"] ``:num -> num -> num``;
   val it = [“$*”, “$+”, “$-”, “ABS_DIFF”, “$DIV”, “$**”, “MAX”, “MIN”,
             “$MOD”]: term list