sub new 
{
	my $class = shift;
	die "Need to be called as a class method" 
	    if ref $class;
	my %params = %{ +shift };

	# Define what params we expect
	my %self = map { $_ => $params{$_} || '' } qw/
	    foo bar baz
	/;

	# Validation

	bless \%self => $class;
}