minor formatting and simplifications

flake.nix

@@ -119,3 +119,4 @@
       };
     });
 }
+

src/convert_xgboost.ml

@@ -236,7 +236,7 @@ let prove_and_print ?memlimit ?timelimit env config prover task =
     let def = Why3.Call_provers.empty_limit in
     {
       Why3.Call_provers.limit_time = timelimit;
-      limit_steps = Option.value ~default:def.limit_steps None;
+      limit_steps = def.limit_steps ;
       limit_mem = memlimit;
     }
   in

src/verification.ml

@@ -435,7 +435,7 @@ let verify ?format ~loadpath ?memlimit ?timelimit ?dataset prover ?prover_altern
     let def = Call_provers.empty_limit in
     {
       Call_provers.limit_time = timelimit;
-      Call_provers.limit_steps = Option.value ~default:def.limit_steps None;
+      Call_provers.limit_steps = def.limit_steps;
       Call_provers.limit_mem = memlimit;
     }
   in
@@ -467,15 +467,14 @@ let verify ?format ~loadpath ?memlimit ?timelimit ?dataset prover ?prover_altern
            else Fmt.(any " " ++ parens string))
           altern)
   in
+  let driver_str = snd config_prover.driver in
+  let driver = Re__Core.replace_string re_config ~by:config_site driver_str in
   let driver =
-    Re__Core.replace_string re_config ~by:config_site (snd config_prover.driver)
-  in
-  let driver =
-    if String.equal driver (snd config_prover.driver)
+    if String.equal driver driver_str
     then Driver.load_driver_for_prover main env config_prover
     else
       Driver.load_driver_file_and_extras main env ~extra_dir:None driver
-          config_prover.extra_drivers
+        config_prover.extra_drivers
   in
   let cwd, mstr_theory = open_file ?format env file in
   let verification_result =