question: public static void registerNewAggregationFunction ( String name , Class < ? extends AggregationFunction > clazz , AggregationFunctionMetaDataProvider metaDataProvider ) { AGGREATION_FUNCTIONS . put ( name , clazz ) ; AGGREGATION_FUNCTIONS_META_DATA_PROVIDER . put ( name , metaDataProvider ) ; }
target:  With this method extensions might register additional aggregation functions if needed.