sub new {
  my ($class) = @_;
  $class = ref($class) || $class;
  (UNIVERSAL::isa($class, __PACKAGE__) 
      || UNIVERSAL::isa(__PACKAGE__, $class)) 
          || die "Oh no you don't!!!!";  
  bless {}, $class;
}

##</code><code>##

Foo::new();
Foo::new("SomeOtherModuleName") ;
Foo::new([]);
Foo::new({});

##</code><code>##

sub new {
  my ($class) = @_;
  $class = ref($class) || $class;
  (defined $class && 
      (UNIVERSAL::isa($class, __PACKAGE__) 
          || UNIVERSAL::isa(__PACKAGE__, $class))) 
              || die "Oh no you don't!!!!";   
  bless {}, $class;
}