could not cast value of type ‘NSNull’ (0x10ae4ede0) to ‘NSNumber’ (0x1080e6e70)

Good evening. I have been working with Xcode and google heat maps lately but I am having issues calling data from firebase to store onto the heatmap. When I run My code, I get the error, could not cast value of type ‘NSNull’ (0x10ae4ede0) to ‘NSNumber’ (0x1080e6e70)

 func addHeatmap()  {      let ref = Database.database().reference(withPath: "JobPost")     ref.observeSingleEvent(of: .value, with: { snapshot in          if !snapshot.exists() { return }           print(snapshot)          print(snapshot.value!)          let location = snapshot.childSnapshot(forPath: "location").value         print(location!)         let lat = snapshot.childSnapshot(forPath: "Latitude").value         let lng = snapshot.childSnapshot(forPath: "Longitude").value         let coords = GMUWeightedLatLng(coordinate: CLLocationCoordinate2DMake(lat as! CLLocationDegrees, lng as! CLLocationDegrees), intensity: 1.0)         self.heatmapLayer.weightedData = [coords]      //   self.GMUHeatmapTileLayer.weightedData = [coords]      })  } 

I was wondering if someone could take a look at what I have an tell me what I have done wrong, or forgot to do. Thank you in advanced.