## sortlistinsert
### Instructions
Create a function named `SortListInsert` , which accepts a pointer to the head of a _sorted_ linked list and an integer.
The function should insert a new element into the list, with its `Data` set to the value of the integer. The element should be inserted so that the linked list remains sorted in ascending order by `Data` . The function should return the head of the list.
Your function will only be tested with sorted linked lists.
### Expected function and structure
```go
func SortListInsert(l *NodeI, data_ref int) *NodeI{
}
```
> You have already defined the `NodeI` structure in the `listsort` exercise.
### Usage
Here is a possible program to test your function :
```go
package main
import (
"fmt"
"piscine"
)
func PrintList(l *piscine.NodeI) {
it := l
for it != nil {
fmt.Print(it.Data, " -> ")
it = it.Next
}
fmt.Print(nil, "\n")
}
func listPushBack(l *piscine.NodeI, data int) *piscine.NodeI {
n := & piscine.NodeI{Data: data}
if l == nil {
return n
}
iterator := l
for iterator.Next != nil {
iterator = iterator.Next
}
iterator.Next = n
return l
}
func main() {
var link *piscine.NodeI
link = listPushBack(link, 1)
link = listPushBack(link, 4)
link = listPushBack(link, 9)
PrintList(link)
link = piscine.SortListInsert(link, -2)
link = piscine.SortListInsert(link, 2)
PrintList(link)
}
```
And its output :
```console
$ go run .
1 -> 4 -> 9 -> < nil >
-2 -> 1 -> 2 -> 4 -> 9 -> < nil >
$
```
