my %set= ('Jan' => {    lower => '1/1/2001',
                                upper => '1/31/2001',
                                upper_inclusive => 1,
                                lower_inclusive => 1,
                        }, # Days in January
                  'Feb' => {    lower => '2/1/2001',
                                upper => '2/28/2001',
                                upper_inclusive => 1,
                                lower_inclusive => 1,
                         }, # Days in February
                );