public static KllHistogramEstimator getEmptyHistogramEstimator(KllHistogramEstimator kllHistogramEstimator) {
    return kllHistogramEstimator == null ? getEmptyHistogramEstimator()
        : getEmptyHistogramEstimator(kllHistogramEstimator.getSketch().getK());
  }
This method creates an empty KLL histogram estimator, using the k parameter from the given estimator.
@param kllHistogramEstimator the estimator used to build the new one
@return an empty KLL histogram estimator, using the k parameter from the given estimator
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/common/histogram/KllHistogramEstimatorFactory.java