#!/usr/bin/env perl 
use strict;
use warnings;

package pm::security;
use Exporter;
our @ISA = ('Exporter');
our @EXPORT = ('banned');

sub banned {
    print "Banned: @_\n";
}
1;

package user;
pm::security->import; # If in separate files, "use pm::security;" will do.

sub do_stuff {
    # We call banned without its package prepended because banned is
    # exported by package pm::security
    banned (@_);
}
1;

package main;
# If in separate files, "use user;" here

# We call do_stuff with its package prepended because do_stuff is not
# exported by package user.
user::do_stuff ('foo', 'bar');