In this chapter, we will cover the following recipes:
- Selecting a model with cross-validation
 - K-fold cross-validation
 - Balanced cross-validation
 - Cross-validation with ShuffleSplit
 - Time series cross-validation
 - Grid search with scikit-learn
 - Randomized search with scikit-learn
 - Classification metrics
 - Regression metrics
 - Clustering metrics
 - Using dummy estimators to compare results
 - Feature selection
 - Feature selection on L1 norms
 - Persisting models with joblib or pickle