@Override public InternalAggregationFunction specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry) { Type valueType = boundVariables.getTypeVariable("V"); QuantileDigestType outputType = (QuantileDigestType) typeManager.getParameterizedType( StandardTypes.QDIGEST, ImmutableList.of(TypeSignatureParameter.of(valueType.getTypeSignature()))); return generateAggregation(valueType, outputType, arity); }