Minor Description
The MLlib ChiSqSelector class is not serializable, and so the example in the ChiSqSelector documentation fails. Also, that example is missing the import of ChiSqSelector. ChiSqSelector should just extend Serializable.
Steps:
1. Locate the MLlib ChiSqSelector documentation example.
2. Fix the example by adding an import statement for ChiSqSelector.
3. Attempt to run -> notice that it will fail due to ChiSqSelector not being serializable.
