     @objc public private(set) var phoneNumber: String
 
     /// The formatted phone number for sending a SMS to the driver.
-    @objc public private(set) var smsNumber: String
+    @objc public private(set) var smsNumber: String?
     
     /// The driver's star rating out of 5 stars.
     @objc public private(set) var rating: Double

        name = try container.decode(String.self, forKey: .name)
        pictureURL = try container.decode(URL.self, forKey: .pictureURL)
        phoneNumber = try container.decode(String.self, forKey: .phoneNumber)
        smsNumber = try container.decode(String.self, forKey: .smsNumber)
        rating = try container.decode(Double.self, forKey: .rating)
    }
}

        case name        = "name"
        case pictureURL  = "picture_url"
        case phoneNumber = "phone_number"
        case smsNumber   = "sms_number"
        case rating      = "rating"
    }

