my $park = new CarPark( filename => 'blah');
  # this will read the file, and (unless the file 
  # is too big or can change in between) save it into 
  # an internal structure suitable for the lookups
  # you are going to do (probably hash keyed on car model)
  # so that you have to read it only once.

my $car = $park->get("pinto");
print $car->horse_power;

$car = $park->get("corvette");
   # a new instance
print $car->horse_power