## thirdtimeisacharm

### Instructions

Write a function `ThirdTimeIsACharm()` that takes a `string` as an argument and returns another `string` with every third character.

- Return the output followed by a newline `\n`.
- If the `string` is empty, return a newline `\n`.
- If there is no third character, return a newline `\n`.

### Expected function

```go
func ThirdTimeIsACharm(str string) string {

}
```

### Usage

Here is a possible program to test your function:

```go
package main

import (
	"fmt"
)

func main() {
	fmt.Print(ThirdTimeIsACharm("123456789"))
	fmt.Print(ThirdTimeIsACharm(""))
	fmt.Print(ThirdTimeIsACharm("a b c d e f"))
	fmt.Print(ThirdTimeIsACharm("12"))
}
```

And its output:

```console
$ go run . | cat -e
369$
$
b e$
$
```