 	}
 	
 	internal class func buildGoogleMapsURL(var #params: [String], callbackURL: NSURL?, callbackName: String?) -> NSURL? {
-		let ok = PXGoogleDirections.canOpenInGoogleMaps()
-		if ok {
+		if PXGoogleDirections.canOpenInGoogleMaps {
 			var scheme = "comgooglemaps"
 			if let cbURL = callbackURL, cbn = callbackName {
 				scheme = "comgooglemaps-x-callback"
-				params.append("x-success=\(cbURL.absoluteString!.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding))")
-				params.append("x-source=\(cbn.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding))")
+				params.append("x-success=\(cbURL.absoluteString!.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)!)")
+				params.append("x-source=\(cbn.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)!)")
 			}
 			let p = (count(params) > 0) ? "?" + "&".join(params) : ""
 			return NSURL(string: "\(scheme)://\(p)")!

			// Missing source and/or destination
			return nil
		}
	}
	
	// MARK: Static functions
	
	/**
	Returns a value indicating whether the device can open places and directions URLs in the Google Maps app or not.
	
	:returns: `true` if the Google Maps app is installed and can open places and directions URLs, `false` otherwise
	*/
	public class func canOpenInGoogleMaps() -> Bool {
		return UIApplication.sharedApplication().canOpenURL(
			NSURL(string: "comgooglemaps://")!) && UIApplication.sharedApplication().canOpenURL(
				NSURL(string: "comgooglemaps-x-callback://")!)
	}
	
	// MARK: Initializers

				// Prepare the base URL parameters with provided arguments
				var params = PXGoogleDirections.handleGoogleMapsURL(center: center, mapMode: mapMode, view: view, zoom: zoom)
				// Add origin and destination
				params.append("saddr=\(f.description.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)!)")
				params.append("daddr=\(t.description.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)!)")
				// Add optional method of transportation, if any
				if let m = mode {
					params.append("directionsmode=\(m)")
