anchor.diff:          stmts @ [ Statement.return'(e) ]
   
       let makeArrowFunctionExpression (args: Arguments) (body: Statement list) : Expression * Statement list =
  +        let args =
  +            match args.Args with
  +            | [] -> Arguments.arguments(args=[ Arg.arg(Python.Identifier("_unit")) ], defaults=[ Expression.none() ])
  +            | _ -> args
  +
           match body with
               | [ Statement.Return({Value=Some expr}) ] -> Expression.lambda(args, expr), []
               | _ ->
  
positive.code:     let getUniqueIdentifier (name: string): Python.Identifier =
          do index.MoveNext() |> ignore
          let idx = index.Current.ToString()
          Python.Identifier($"{name}_{idx}")
  
      let toSnakeCase = applyCaseRule CaseRules.SnakeCase
  
  
negative.code:                        OptimizeTailCall = fun () -> isTailCallOptimized <- true
                         BoundVars = ctx.BoundVars.EnterScope() }
  
          // printfn "Args: %A" (name, args, body)
          let body =
              if body.Type = Fable.Unit then
                  transformBlock com ctx (Some ReturnUnit) body
  