use strict;
use warnings;
package Garage;

sub new {
  my $pkg = shift;
  my $self = {
    all_cars => {},  # store cars key'd by license plate (uuid)
  }
  blese $self, $pkg;
  return $self;
}

sub add_car {
  my ($self, $car) = $@;
#... add car key'ed by license plate or uuid
}

sub del_car {
  my ($self, $uuid) = $@
  delete $self->get_cars->{$uuid};
}

sub get_cars {
  my $self = shift;
  return $self->{all_cars};
}

sub get_car {
  my ($self, $uuid) = $@;
  my $cars = $self->get_cars;
  die "Car with plate $uuid is not in the garage!\n\n" if not $cars->{$uuid}; # die can throw a reference also, so there you can do the exception thing in the caller
  return $cars->{$uuid};
}

sub count_cars {
  my $self = shift;
  my $cars_ref = $self->get_cars;
  my $count = @{keys %$cars_ref};
  return $count;
}

# add other "collective" methods

1;