##
use Business::ISSN qw(is_valid_checksum);
my $issn = '0742-4477';
print "Valid = " . is_valid_checksum($issn);
##
##
"is_valid_checksum" is not exported by the Business::ISSN module
Can't continue after import errors at test.pl line 1
BEGIN failed--compilation aborted at test.pl line 1.