docs: public static Map<String, String> normalizeColumnStats(ColumnStats columnStats) {
  		Map<String, String> stats = new HashMap<>();
  		if (columnStats.getNdv() != null) {
  			stats.put(DISTINCT_COUNT, String.valueOf(columnStats.getNdv()));
  		}
  		if (columnStats.getNullCount() != null) {
  			stats.put(NULL_COUNT, String.valueOf(columnStats.getNullCount()));
  		}
  		if (columnStats.getAvgLen() != null) {
  			stats.put(AVG_LENGTH, String.valueOf(columnStats.getAvgLen()));
  		}
  		if (columnStats.getMaxLen() != null) {
  			stats.put(MAX_LENGTH, String.valueOf(columnStats.getMaxLen()));
  		}
  		if (columnStats.getMaxValue() != null) {
  			stats.put(MAX_VALUE, String.valueOf(columnStats.getMaxValue()));
  		}
  		if (columnStats.getMinValue() != null) {
  			stats.put(MIN_VALUE, String.valueOf(columnStats.getMinValue()));
  		}
  		return stats;
  	}