use strict;
use warnings;
use validate_options; # Factory Method

sub new{
    my $class = shift;
    my %opts  = @_;
    my $self = bless{}, $class;
    $self->validate_options({name => 'foo'}, \%opts);
}


my $o = main->new( foo => 'bar' );
# new: 'foo' is not a valid option name at ...


my $o = main->new( name => 'foo' ); # OK!