`qw()`

        use base  ('Person', 'Security::Agent', 'Programmer');

There is too much punctuation here
A list of class names or other words is common
Abbreviation:

        use base  qw(Person Security::Agent Programmer);

qw is Quoted Words
qw(...) is like split /\s+/, '...'
Another typical use:

        use Geometry qw(circle_area circumference);

Another:

        @months = qw(January   February March    April
                     May       June     July     August
                     September October  November December);