An [[wp:International_Securities_Identification_Number|International Securities Identification Number]] (ISIN) is a unique international identifier for a financial security such as a stock or bond. 


;Task:
Write a function or program that takes a string as input, and checks whether it is a valid ISIN.

It is only valid if it has the correct format,   ''and''   the embedded checksum is correct.

Demonstrate that your code passes the test-cases listed below.


;Details:
The format of an ISIN is as follows:

<!-- BEGIN DIAGRAM -->
<div style="margin:3em; white-space:nowrap; line-height:20px">
<div><span style="font-size:20px; font-family:'Lucida Console',Monaco,monospace"><span style="color:green; margin:0 0 0 10px">┌───────────── </span></span><span style="color:green">a 2-character ISO country code (A-Z)</span></div>
<div><span style="font-size:20px; font-family:'Lucida Console',Monaco,monospace"><span style="color:green; margin:0 -10px 0 10px">│</span>&nbsp;<span style="color:blue; margin:0 0 0 10px">┌─────────── </span></span><span style="color:blue">a 9-character security code (A-Z, 0-9)</span></div>
<div><span style="font-size:20px; font-family:'Lucida Console',Monaco,monospace"><span style="color:green; margin:0 -10px 0 10px">│</span>&nbsp;<span style="color:blue; margin:0 -5px 0 10px">│</span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span style="color:red; margin:0 0 0 5px">┌── </span></span><span style="color:red">a checksum digit (0-9)</span></div>
<div style="font-size:20px; font-family:'Lucida Console',Monaco,monospace"><span style="background: #d9ebd9; color:green; border:solid 1px green; margin:0 1px">AU</span><span style="background:#e0e0ff; color:blue; border:solid 1px blue; margin:0 1px">0000XVGZA</span><span style="background:#feefef; color:red; border:solid 1px red; margin:0 1px">3</span></div>
</div>
<!-- END DIAGRAM -->


For this task, you may assume that any 2-character alphabetic sequence is a valid country code.

The checksum can be validated as follows:
# '''Replace letters with digits''', by converting each character from base 36 to base 10, e.g. <code>AU0000XVGZA3</code> &rarr;<code>1030000033311635103</code>.
# '''Perform the Luhn test on this base-10 number.'''<br>There is a separate task for this test: ''[[Luhn test of credit card numbers]]''.<br>You don't have to replicate the implementation of this test here &nbsp; ─── &nbsp; you can just call the existing function from that task. &nbsp; (Add a comment stating if you did this.)


;Test cases:
:::: {| class="wikitable"
! ISIN
! Validity
! Comment
|-
| <tt>US0378331005</tt>  || valid || 
|-
| <tt>US0373831005</tt>  || not valid || The transposition typo is caught by the checksum constraint.
|-
| <tt>U50378331005</tt>  || not valid || The substitution typo is caught by the format constraint.
|-
| <tt>US03378331005</tt> || not valid || The duplication typo is caught by the format constraint.
|-
| <tt>AU0000XVGZA3</tt>  || valid || 
|-
| <tt>AU0000VXGZA3</tt>  || valid || Unfortunately, not ''all'' transposition typos are caught by the checksum constraint.
|-
| <tt>FR0000988040</tt>  || valid || 
|}

(The comments are just informational. &nbsp; Your function should simply return a Boolean result. &nbsp; See [[#Raku]] for a reference solution.)


Related task:
* [[Luhn test of credit card numbers]]


;Also see:
* [https://www.isincodes.net/validate-isin/ Interactive online ISIN validator]
* Wikipedia article: [[wp:International_Securities_Identification_Number|International Securities Identification Number]]
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