public function getValidLowerCasedIssn() {
return array(
array(
'2162-321x',
),
array(
'2160-200x',
),
array(
'1537-453x',
),
array(
'1937-710x',
),
array(
'0002-922x',
),
array(
'1553-345x',
),
array(
'1553-619x',
),
);
}