Version 1.03
  06/11/06 - Fixed a typo in the documentation for issue_num().

Version 1.02
  04/01/02 - Fixed error in test cases of t/04-bad.t. It was looking for the
    string "not correct" from Algorith::LUHN, which changed it to "incoorect."
    Test now looks for either string.

Version 1.01
  03/27/02 - Fixed error() to return undef for valid CUSIP, as documented.
    Set $ERROR to undef after successful is_valid() call.

Version 1.00
  11/18/01 - Added the error() method.

Version 0.03
  05/09/01 - Added t/05-acc.t test.

Version 0.02

 05/03/01 - Added a lot of validations in is_valid. Added new test t/04-bad.t
   to check new validations.

 05/01/01 - Changed the way the list of A..Z valid_chars is generated to be
    more explicit.