I'm learning Kotlin , and I'm trying to undetstand `Ranges`

I created a range of `String` as follows

```
val alpha = "A".."Z"

```

I want to print this for that I wrote 

```
for (item in alpha) println(item)

```

But it gives the error 

> 
> Error:(13, 18) Kotlin: For-loop range must have an 'iterator()' method
> 
> 
> 

Can anyone help, how to print this range?