title: Sklearn GridSearchCV, class_weight not working for unknown reason :(
body: <p>Trying to get <code>class_weight</code> going . I know the rest of the code works, its just the <code>class_weight</code> that gives me the error:</p>
  
  <pre><code>    parameters_to_tune = ['min_samples_split':[2,4,6,10,15,25], 'min_samples_leaf':[1,2,4,10],'max_depth':[None,4,10,15],
                                               ^
  SyntaxError: invalid syntax
  </code></pre>
  
  <p>Here is my code</p>
  
  <pre><code>clf1 = tree.DecisionTreeClassifier()
   parameters_to_tune = ['min_samples_split':[2,4,6,10,15,25], 'min_samples_leaf':[1,2,4,10],'max_depth':[None,4,10,15],
   'splitter' : ('best','random'),'max_features':[None,2,4,6,8,10,12,14],'class_weight':{1:10}]
  clf=grid_search.GridSearchCV(clf1,parameters_to_tune)
  clf.fit(features,labels)
  print clf.best_params_
  </code></pre>
  
  <p>Does anyone spot the mistake I am making ? </p>