presto-main/src/main/java/io/prestosql/metadata/SignatureBuilder.java/SignatureBuilder/operatorType
class SignatureBuilder:    public SignatureBuilder operatorType(OperatorType operatorType)
    {
        this.name = mangleOperatorName(requireNonNull(operatorType, "operatorType is null"));
        this.kind = SCALAR;
        return this;
    }