I am getting this error message about my String `greeting` function

Hi Romi, let's go step by step

at the begging of a challenge you have this piece of code

func greeting() {
    println("Hello")
}

First task is: Modify the function named greeting to accept a parameter. Name the parameter person which is of type String.

We need to add person: String in parentheses like this

func greeting(person: String) {
    println("Hello")
}

Second task is: Modify the println statement within the greeting function to use the variable person. For example, if you pass a person named "Tom" to the function then it should display: Hello Tom. (Hint: you must use string interpolation).

We need to add (person) to a string in println like this

func greeting(person: String) {
    println("Hello \(person)")
}

And finally third task is: Call the function greeting and pass it the string "Tom".

All we need to do is to call a function like this: greeting("Tom")

This is whole correct code

func greeting(person: String) {
    println("Hello \(person)")
}

greeting("Tom")