No VAT validation for South Africa.

[ernestodavidph]

I've being working with this library (awesome btw), and realized it has implemented TIN and IDNR validations for South Africa, but not VAT validations, which have another format (length 10 and start with 4, no checksum).

[koblas]

Your VAT ID is a unique identifying number that you may request from your government by registering for VAT in South Africa. It is a 10-digit number that starts with a 4 and looks like this, for example: 4999999999.