Override methods can not have default values in Kotlin

This code
```
class Test {
    override func dostuff(x: Int = 5) {
    }
}
```

gets transpiled as 
```
class Test {
    
    override fun dostuff(x: Int = 5) {}
}
```

But that is not valid Kotlin for overriden methods. It should be:

```
class Test {
    
    override fun dostuff(x: Int) {}
}

```