title: Retrain Multiclassification ITransformer
body: <p>I created a ITransformer model based on the SdcaMaximumEntropy trainer from the MulticlassClassification :</p>
  
  <pre><code>var trainingPipeline = pipeline.Append(mlContext.MulticlassClassification.Trainers.SdcaMaximumEntropy())
                      .Append(mlContext.Transforms.Conversion.MapKeyToValue("PredictedLabel"));
  ITransformer trainedModel = trainingPipeline.Fit(splitTrainSet);
  </code></pre>
  
  <p>Now I want to retrain it with the Fit method by applying the original model parameters : </p>
  
  <pre><code>var originalModelParameters = ((MulticlassPredictionTransformer&lt;object&gt;)model).Model as MaximumEntropyModelParameters;
              model = mlContext.MulticlassClassification.Trainers.SdcaMaximumEntropy().Fit(newData, originalModelParameters);
  </code></pre>
  
  <p>But I get an error on the Fit method :</p>
  
  <blockquote>
    <p>No overload for method 'Fit' takes 2 arguments</p>
  </blockquote>
  
  <p>So I'm aware that the Fit method from the SdcaMaximumEntropy trainer doesn't have the required Fit method with 2 arguments, but I am wondering how can I retrain my multiclassification model without it ?</p>