private Classifiable createMetaClassifiable(Classifiable classifiable) throws Exception {
   Map<String, Double> classificationResult = new HashMap<>();
   for (Classifier originalClassifier : classifier) {
     classificationResult.putAll(originalClassifier.estimate(classifiable));
   }
   return new DefaultClassifiable(classificationResult);
 }
 @Override
 public Map<String, Double> estimate(Classifiable classifiable) throws Exception {
   return metaClassifier.estimate(createMetaClassifiable(classifiable));
 }