title: pipeline for RandomOversampler, RandomForestClassifier & GridSearchCV
body: <p>I am working on a text binary classification problem. As the classes are highly imbalanced, I have to go for sampling techniques like RandomOversampler(). Then for classification I would use RandomForestClassifier () whose parameters need to be tuned using GridSearchCV().
  I am trying to create a pipeline to do these in order but failed so far. It throws 'invalid parameters'.</p>
  
  <pre><code>param_grid = {
               'n_estimators': [5, 10, 15, 20],
               'max_depth': [2, 5, 7, 9]
           }
  grid_pipe = make_pipeline(RandomOverSampler(),RandomForestClassifier())
  grid_searcher = GridSearchCV(grid_pipe,param_grid,cv=10)
  grid_searcher.fit(tfidf_train[predictors],tfidf_train[target])
  </code></pre>