presto-main/src/main/java/io/prestosql/operator/aggregation/AggregationImplementation.java/AggregationImplementation/parseImplementation
class AggregationImplementation:        public static AggregationImplementation parseImplementation(
                Class<?> aggregationDefinition,
                AggregationHeader header,
                Class<?> stateClass,
                Method inputFunction,
                Optional<Method> removeInputFunction,
                Method outputFunction,
                Method combineFunction,
                Optional<Method> stateSerializerFactoryFunction)
        {
            return new Parser(aggregationDefinition, header, stateClass, inputFunction, removeInputFunction, outputFunction, combineFunction, stateSerializerFactoryFunction).get();
        }