To use PPO during debugging, use it similar to the way you would use
Data::Dumper:

perl -d myscript.pl

DB<1> use Data::PrettyPrintObjects
...
DB<>  p PPO($var)

If you will be doing a lot of debugging, you may want to create a
YAML file named '.ppo.yaml' in the current directory containing
PPO_ConfigFile options for how to display an object.