title: how to save a scikit-learn pipline with keras regressor inside to disk?
body: <p>I have a scikit-learn pipline with kerasRegressor in it:</p>
  
  <pre><code>estimators = [
      ('standardize', StandardScaler()),
      ('mlp', KerasRegressor(build_fn=baseline_model, nb_epoch=5, batch_size=1000, verbose=1))
      ]
  pipeline = Pipeline(estimators)
  </code></pre>
  
  <p>After, training the pipline, I am trying to save to disk using joblib...</p>
  
  <pre><code>joblib.dump(pipeline, filename , compress=9)
  </code></pre>
  
  <p>But I am getting an error:</p>
  
  <blockquote>
    <p>RuntimeError: maximum recursion depth exceeded</p>
  </blockquote>
  
  <p>How would you save the pipeline to disk?</p>