package Car;
use base Vehicle;
@ISA = 'Vehicle';

use strict;
use warnings;
use Carp;


my %valid = map { $_ => 1 } qw( Wheels Doors Color Passengers );
my %ro    = map { $_ => 1 } qw( Wheels );

sub _init {
    my ($self, %arg) = @_;
    for my $option ( keys %arg ) {
        croak "$option is not valid" if ! $self->_valid( $option );
        $self->{$option} = $arg{$option};
    }
    $self->{Wheels} = 4;
    return;
}

sub _read_only {
    my ($self, $option) = @_;
    return defined $ro{$option} ? 1 : 0;
}

sub _valid {
    my ($self, $option) = @_;
    return defined $valid{$option} ? 1 : 0;
}
1;