use Scalar::Util 'reftype';

sub new {
    my ( $class, $args ) = @_;
    $args = {} unless defined $args;
    unless ( 'HASH' eq reftype $args ) {
        croak "Argument to new() must be a hash reference";
    }
    my $self = bless {} => $class;
    while ( my ( $key, $value ) = each %$args ) {
        $self->$key($value);
    }
    return $self;
}