     */
     public func createClassifier(
         name: String,
-        classnamePositiveExamples: URL,
+        positiveExamples: [PositiveExample],
         negativeExamples: URL? = nil,
         failure: ((Error) -> Void)? = nil,
         success: @escaping (Classifier) -> Void)

        let multipartFormData = MultipartFormData()
        let nameData = name.data(using: String.Encoding.utf8)!
        multipartFormData.append(nameData, withName: "name")
        multipartFormData.append(classnamePositiveExamples, withName: "classname_positive_examples")
        if let negativeExamples = negativeExamples {
            multipartFormData.append(negativeExamples, withName: "negative_examples")
        }

    */
    public func updateClassifier(
        classifierID: String,
        positiveExamples: [PositiveExample]? = nil,
        negativeExamples: URL? = nil,
        failure: ((Error) -> Void)? = nil,
        success: @escaping (Classifier) -> Void)
    {
        // construct body
        let multipartFormData = MultipartFormData()
        if let positiveExamples = positiveExamples {
            positiveExamples.forEach { example in
                multipartFormData.append(example.examples, withName: example.name + "_positive_examples")
            }
        }
        if let negativeExamples = negativeExamples {
            multipartFormData.append(negativeExamples, withName: "negative_examples")
