code: def to_simple_rdd(sc, features, labels):
      
      pairs = [(x, y) for x, y in zip(features, labels)]
      return sc.parallelize(pairs)
docs: Convert numpy arrays of features and labels into
      an RDD of pairs.
  
      :param sc: Spark context
      :param features: numpy array with features
      :param labels: numpy array with labels
      :return: Spark RDD with feature-label pairs