These entries are queried from radb.net using whois, you can try my project getting these.
:AS-SERTEX as-set: AS-SERTEX descr: SERTEX as-set members: AS64421 members: AS31519 tech-c: DUMY-RIPE admin-c: DUMY-RIPE mnt-by: SERTEX-MNT created: 2019-06-06T11:53:44Z last-modified: 2019-07-26T20:33:18Z source: RIPE remarks: **************************** remarks: * THIS OBJECT IS MODIFIED remarks: * Please note that all data that is generally regarded as personal remarks: * data has been removed from this object. remarks: * To view the original object, please query the RIPE Database at: remarks: * http://www.ripe.net/whois remarks: ****************************