my $url = $opt->{url} || $::Variable->{USPS_URL} || 'http://Production.ShippingAPIs.com/ShippingAPI.dll';
my $container = $opt->{container} || $::Variable->{USPS_CONTAINER} || 'None';
my $machinable = $opt->{machinable} || $::Variable->{USPS_MACHINABLE} || 'False';

$service = uc $service;
if (! $supported_services{$service}) {
$error_msg .= "unknown service type $service.";
return;
  }

  my $size = uc ($opt->{size} || $::Variable->{USPS_SIZE} || 'REGULAR');
  if (! $package_sizes{$size}) {
$error_msg .= "unknown package size $size.";
return;
}