I have written the following method in Swift 3

```
func postFormData(url : String, parameters: Parameters!, headers : HTTPHeaders!, completionHandler : (response : Any,  error: Any)) {

    Alamofire.request(url, method : .post, parameters: parameters, headers: headers)
        .responseJSON { response in

            if let status = response.response?.statusCode {
                switch(status)
                {
                    let data = result as! NSDictionary
                    case 200:
                        if let result = response.result.value {
                            completionHandler(data)
                        }
                    default:
                        completionHandler(nil, data)
                }
            }
    }

}

```

1. I get an error at `completionHandler(data)` stating `Cannot call value of non-function type '(response: Any, error Any)'`
2. Is writing `completionHandler(nil, data)` to handle errors the best practice?

PS : I am new to `iOS` and `Swift 3`