I am currently building my binary tree in F#, and I'm almost finished. I'm on the last assignment of this task, where I am supposed to make a string representation of the binary tree. Meaning that the tree should be presented like this: 

Example: `("node" "value" ("node" "value" "Empty" "Empty") Empty)` <- A tree with a rootnode that has a left subtree with a node that has two empty subtrees, and an empty right subtree.

My tree looks like this:

```
 type Btree<'a when 'a: comparison> = 
 |Node of  'a * Btree<'a> *Btree<'a> 
 |Leaf of 'a 
 |EmptyTree 

```

This is how far I've gotten: 

```
let rec treeToString bintree = 
    match bintree with
    |EmptyTree -> "Empty" //Check if the tree is empty
    |Node(inner, left, right) when inner = 0 -> "Empty"
    |Leaf x-> "Node"+x.ToString() //Returns "Node" and its value
    |Node(inner, left, right) when inner <> 0-> treeToString left //Need some kind of output here, but what?
    |Node(inner, left, right) when inner <> 0->treeToString right

```

My method only returns one value, so the actual problem with my solution is getting the recursive part right. 

So my question is: What am I doing wrong here?