LetExp([
 VarDec(rate,true,NONE,
  IntExp(2)),
 FunctionDec[
  (getCost,[
   (total,true,int)],
   SOME(int),
   LetExp([
    VarDec(newrate,true,NONE,
     IntExp(10)),
    FunctionDec[
     (getExtra,[],
      NONE,
      IfExp(
       OpExp(GtOp,
        VarExp(
         SimpleVar(total)),
        IntExp(100)),
       AssignExp(
        SimpleVar(rate),
        IntExp(5)),
       AssignExp(
        SimpleVar(rate),
        VarExp(
         SimpleVar(rate)))))]],
    SeqExp[
     CallExp(getExtra,[]),
     OpExp(TimesOp,
      OpExp(TimesOp,
       VarExp(
        SimpleVar(newrate)),
       VarExp(
        SimpleVar(total))),
      VarExp(
       SimpleVar(rate)))]))]],
 OpExp(PlusOp,
  CallExp(getCost,[
   IntExp(250)]),
  IntExp(20)))