http://cpansearch.perl.org/src/MSULLAND/Device-USB-PCSensor-HidTEMPer-0.03/lib/Device/USB/PCSensor/HidTEMPer/TEMPer.pm

...

use constant SUPPORTED_DEVICES => {
    0x5b    => {
        'name'      => 'HidTEMPerNTC',
        'module'    => 'Device::USB::PCSensor::HidTEMPer::NTC'
    },
    0x58    => {
        'name'      => 'HidTEMPer',
        'module'    => 'Device::USB::PCSensor::HidTEMPer::TEMPer'
    }
};


..

# This functions detects the correct object to be created and returned.
# Returns undef if not supported device was found.
sub _init_device
{
    my $prototype   = Device::USB::PCSensor::HidTEMPer::Device->new( $_[0] );
-   my $parameters  = (SUPPORTED_DEVICES)[0]{$prototype->identifier()};
+   my $parameters  = SUPPORTED_DEVICES->{$prototype->identifier()};


    return undef unless defined $parameters;

    bless $prototype, $parameters->{module};
    return $prototype->init();
}