Strange () in output

```nim
import cascade

type
  Sas = object

func qwe(sas: Sas) = debugEcho "qwe"
func rty(sas: Sas) = debugEcho "rty"

let bar = cascade Sas():
  qwe()
  if 1 == 1:
    rty()
    echo "sas"
    echo "qwe"
    debugEcho "zxc"
    var x = 1
    echo x + 654
 ```
 Output:  
 ```
qwe
rty
()sas
()qwe
()zxc
()655
```