$ cat -n /usr/lib/perl5/site_perl/5.10/Argv.pm | sed -n 304,311p
 304	$self = {};
 305	if ($proto ne __PACKAGE__) {
 306	    # Inherit class attributes from subclass class attributes.
 307	    no strict 'refs';
 308	    for (keys %$proto) {
 309		$self->{$_} = $proto->{$_};
 310	    }
 311	}