_pingPrinter is not a function.

I am using the pingPrinter function like this

`pingPrinter(printerIp).then(()=>{
    console.log("found the printer");
}).catch((err)=> {
    console.log("Printer is dead", err);
})`

It gives the following error
```
Printer is dead [TypeError: _pingPrinter is not a function. (In '_pingPrinter(ip)', '_pingPrinter' is undefined]
```