In Swift, can I detect if a CLLocation is valid or not?

I am passing a location to another UIViewController which has a MapView using prepareForSegue. I call this receivedLocation. The map centers on the location that is passed. If the user clicks a button to take them to the map without first sending a location, won't this fail?

How can I test to see if receivedLocation actually contains data, so that I can set the map to center on something else if it's empty?

Would creating a Boolean variable, and initially setting it false but turning it to true when passing a location and testing that work as I desire?

I see something called CLLocationCoordinateIsValid is available, but its parameter is a 2DCoordinate, where I run into the same problem of testing whether or not receivedLocation.

I'm fairly new at this and tried looking for an answer already but couldn't find an appropriate one. Thank you!

import UIKit
import MapKit
import CoreLocation

class mapViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate {

    @IBOutlet var map: MKMapView!
    @IBOutlet var notes: UITextView!

    var receivedLocation = CLLocation()
    var annotation = MKPointAnnotation()
    var currentManager:CLLocationManager!

    var latitute:CLLocationDegrees = CLLocationDegrees()
    var longitude:CLLocationDegrees = CLLocationDegrees()

    override func viewDidLoad() {
        super.viewDidLoad()

        map.layer.cornerRadius = 12.0
        notes.layer.cornerRadius = 12.0

        currentManager = CLLocationManager()
        currentManager.delegate = self
        currentManager.desiredAccuracy = kCLLocationAccuracyBest
        currentManager.startUpdatingLocation()

        if CLLocationCoordinate2DIsValid(receivedLocation.coordinate) {

            latitute = receivedLocation.coordinate.latitude
            longitude = receivedLocation.coordinate.longitude
            annotation.coordinate.latitude = receivedLocation.coordinate.latitude
            annotation.coordinate.longitude = receivedLocation.coordinate.longitude
            map.addAnnotation(annotation)

        } else {

            latitute = currentManager.location.coordinate.latitude
            longitude = currentManager.location.coordinate.longitude
        }

        var latDelta: CLLocationDegrees = 0.01
        var lonDelta: CLLocationDegrees = 0.01
        var span:MKCoordinateSpan = MKCoordinateSpanMake(latDelta, lonDelta)
        var location : CLLocationCoordinate2D = CLLocationCoordinate2DMake(latitute, longitude)
        var region: MKCoordinateRegion = MKCoordinateRegionMake(location, span)       
        map.setRegion(region, animated: false)

    }

So far this is not working for me. CLLocationCoordinate2DIsValid always returns true and centers around an island, as well as adds an annotation to that weird spot.