sub new
{
    my $class = shift;
    my %params = @_;
    my $protected = sub {
        croak qq{Attempt to access protected data "$_[2]"} unless caller->isa(__PACKAGE__);
    };
    my $wiz = wizard(
        store   => $protected,
        fetch   => $protected,
        exists   => $protected,
        delete   => $protected,
    );
    my %self;
    cast %self, $wiz;
    my $self = \%self;
    bless $self, $class;
    $self->$_($params{$_}) foreach keys %params;
    return $self;
}