has_field 'date_time' => (
    type => 'Compound',
    apply => [
               {
                   transform => sub { DateTime->new( shift ) },
                   message => 'This is not a correct date',
               }
               {
                   check => sub { shift->day_of_week == 1 },
                   message => 'Only Mondays allowed',
               }
             ],
);
has_field 'date_time.year' => (
    type => 'Integer',
);
has_field 'date_time.month' => (
    type => 'Integer',
    apply => [ { check => sub { my $month = shift; return $month > 0 && $month <= 12 } ]
);
has_field 'date_time.day' => (
    type => 'Integer',
    apply => [ { check => sub { my $day = shift; return $day > 0 && $day <= 31 } ]
);