package TestPkg;
use Dispatch;

sub sub_a {
    # ...
}

sub sub_b {
    # ...
}

sub _sub_b_helper { # not part of the table!
    # ...
}

sub sub_c {
    print $_[0];
}

package main;
my $table = create_dptable TestPkg; # or TestPkg::create_dptable();
$table->{sub_c}->("Hello!");