adding some basic handling that unfolds a conjecture in a locale before testing it with quickcheck
(* Classical Higher-order Logic -- batteries included *)
use_thys ["Library", "List_Cset", "List_Prefix", "List_lexord", "Sublist_Order",
  "Product_Lattice",
  "Code_Char_chr", "Code_Char_ord", "Code_Integer", "Efficient_Nat"(*, "Code_Prolog"*),
  "Code_Real_Approx_By_Float" ];