Add support for Singapore TIN

[unho]

• https://www.oecd.org/tax/automatic-exchange/crs-implementation-and-assistance/tax-identification-numbers/Singapore-TIN.pdf
• https://www.uen.gov.sg/ueninternet/faces/pages/admin/aboutUEN.jspx
• https://carina.gov.hr/UserDocsImages//dokumenti/CTVP//Mogu%C4%87e%20varijante%20UEN%20brojeva.pdf
• https://sleek.sg/2019/10/02/what-is-uen-in-singapore/
• https://wiki.scn.sap.com/wiki/display/CRM/Singapore
• https://www.sgbt.lu/fileadmin/user_upload/SGBT/PDF/Compliance/CRS_2018/20191031_TIN_Leaflet_EN.pdf

Search company online:

• https://www.uen.gov.sg
• https://www.iras.gov.sg/irashome/GST/GST-registered-businesses/Other-services/Checking-if-a-Business-is-GST-Registered/

Validation:

• https://gist.github.com/mervintankw/90d5660c6ab03a83ddf77fa8199a0e52

Examples:

• Database with real UEN numbers: https://data.gov.sg/dataset/entities-with-unique-entity-number

  T19LL0797J T18LL1393C T18FC0083E T17LL2098G T17LL1494G T17LL0235L T16LL1853E T16LL1392H T16LL0695L T16LL0053J T15LL1956A T15LL1855C T15LL1753J T14LL1800D T14LL1743K T14LL1681C T14LL1237A T14LL0839C T14FC0094H T13LL0828H T12LL2127H T12LL2046J T12LL0781D T12LL0595L T11LL2079G T11LL1971L T11LL1149C T11LL0668C T10LL1848E T10LL1480E T10LL1442K T10LL1400J T10LL1392L T10LL1298G T08LL1615B T08LL1558H T08LL0979J T07LL0668H T07LL0309A T06LL0476A T05LL0174J T01FC6132D S96FC5128K S85FC3621C S73FC2294C S68FC1890G S64FC1644H S16FC0121D 53400433D 53399659K 53399638D 53399589B 53398169K 53397681B 53395867M 53395684J 53394981E 53393519M 53393390X 53393038C 53392959L 53385401J 53384425L 53384385E 53384227A 53383991B 53383940L 53382783C 53382124W 53381136L 53380232J 53377824K 53377498E 53377389W 53374706J 53374421X 53374181E 53374159M 53373737X 53373376J 53373278J 53372960B 53372845B 53372084B 53371741L 53369357L 53369142K 53368090E 53366669D 53366537W 53365157C 53365141K 53365050W 53363709X 53363526L 53363453M 53360906B 53360367J 53360246K 53360148K 53359796W 53359192M 53358936C 53358412D 53358098J 53357813B 53357438B 53354912D 53352926C 53352847W 53351301D 53349478L 53347826W 53346756W 53346603B 53346524M 53344927L 53343978K 53343146L 53341298J 53341233A 53341171L 53340486W 53340108M 53339826J 53339287W 53338593L 53338455M 53337959L 53337633E 53337452M 53337382D 53337313A 53336671B 53336471W 53334750E 53333709K 53333269M 53330210B 53329865B 53329644K 53328294B 53327223L 53326012D 53325701L 53325085D 53324543E 53322268X 53321041X 53320609W 10841100A 10839500J 10655900A 10555800A 10528100W 10482100X 10415300L 10362000A 10185500A 10080700C 09623000B 09402000X 08791100X 08511500B 08301600K 08268300W 07846200B 07609900L 07392800C 07330000D 07179600B 07088800X 07059900M 07046800A 07038800L 06905300J 06540200J 06273700K 06108900A 06018700W 05827100K 05796700L 05682800D 05598000K 05473700A 05346600D 05328700B 05040200E 05016600W 03989700A 03875300J 03122200E 03076400M 02708900B 02570100B 02143900A 01680100L 01402200A 00416700K 00192200M

• Company list https://www.sgpbusiness.com/browse/A

  201602902K 201316157E

• Company list https://directory.singaporefintech.org/directory/listing

  201732074H 201620388N 200509725E 201605323H 201543956D 201330175G 201626104W S27FC0556D 201102634H 201704172Z 201814975K 200001838R 200204038R 201533374C 201731364D 201506999D 201810763C 200612239R 201808454H 201831257M 201509563K 198700821N 201723655Z 201801863N 200402245Z 201528593H 201830835R 201422013M 200601141M 201525866W 201508961K 201608874E 201528239N 201507276Z 201405619W 201616811C 201539125W 201621244C 201813990E 201312700G 201107298M 201529785D 201610912H 201819215N 201613871H 201814325Z 201314109K S73FC2302A 201427857E 199201624D 199903512M 201931750M 199701117H 201506513W 200717119C 201610327H 201227749M 201434292D 201008183D S99FC5759D 201630906R 200613692K 201128195W 201630570C 200003956G 199607747H 201722949W T08LL0721A T09LL1649F 201838963W

• Company list https://techasean.io/en/entity/?q=&countryOrigin=Singapore&role=

  201933247R 201317775M 200911532W 201118211H 53143018M 201430557E 201421015W 201703509H

• https://graduatestudies.smu.edu.sg/sites/graduatestudies.smu.edu.sg/files/List%20of%20Projects%20on%20PIP_0.pdf

  200311327H 201828636K 201504218R 201728348W 201114628K 198101793G 201026348Z 199103870C 201105107Z 201221002E 200923096R 201706114W 198601642R 201730487Z

• Found on the Internet:

  T01SS0121K 201524437R 200503573Z 201001206N 201323386K 201927572K 201505714C 201902616N 201834016K 201804195C T08LL0005E 201729145M 201539692G 201831267E 201530032R S65SS0033F 199700895N 199409389H 201928835M 201422211Z 201612228W 200806526H 201735853W 199407631H 53380578C 201538146W S66SS0041B T08LL0003B 201709179W 200004389G S86SS0040A 201225997K 201541306Z S60FC1376L

[unho]

Contacted the official authority to get details on how the check letter is calculated. The response is:

We do not release the UEN algorithm that calculate the check alphabet.

[unho]

Sent another email to a different email address. Crossing fingers.

[unho]

Got a response to my second email. They are still not disclosing the algorithm. I have replied back. Lets hope they reconsider.

[unho]

@arthurdejong Got the final reply. They are not disclosing the algorithm because they don't own the algorithm. They sent me to the owners, which is the people that I had already contacted before. So we are not getting it. We will have to go with what is PRed in #203