#!/usr/bin/env perl
package a;
use strict;
use warnings;
use lib (',');

sub double {
  return 2*$_[0];
}


package main;
use strict;
use warnings;
use feature 'say';
use Cowbell qw(thrice);

sub double {
  return "$_[0]" . $_[0];
}

sub twice {
  return a::double($_[0]);
}


say a::double(2); #4
say double(2);  #22
say thrice(2); #6

say thrice(2) - twice(3) + double(22) + 1;