use strict;
use warnings;

# Enable special comments for debugging and reporting:
use Smart::Comments;

my $data_structure = {
    a => [ 1, 2, 3 ],
    b => [
        { X => 1, Y => 2 },
        {
            X => [ 1, 2, 3 ],
            Y => [ 4, 5, 6 ],
            Z => [ 7, 8, 9 ]
        },
    ],
};

# the following is a "smart comment" which causes a dump of the expression, using Data::Dumper:
### $data_structure