Task

For each number list of 6-digit SEDOLs, calculate and append the checksum digit.



That is, given this input:

710889
B0YBKJ
406566
B0YBLH
228276
B0YBKL
557910
B0YBKR
585284
B0YBKT
B00030

Produce this output:

7108899
B0YBKJ7
4065663
B0YBLH2
2282765
B0YBKL9
5579107
B0YBKR5
5852842
B0YBKT7
B000300

Extra credit

Check each input is correctly formed, especially with respect to valid characters allowed in a SEDOL string.



Related tasks

   Luhn test
   ISIN


         ╔════════════════════════════════════════════════════════════════════╗
         ║  If the SEDOL is 6 characters, a check digit is added.             ║
         ║                                                                    ║
         ║  If the SEDOL is 7 characters, a check digit is created and it's   ║
         ║  verified that it's equal to the check digit already on the SEDOL. ║
         ╚════════════════════════════════════════════════════════════════════╝
