use strict;
use Data::Dumper;
my $package_name = "Data";
print Dumper \%{$::{$package_name."::"}};

use strict;
use Data::Dumper;
my $top_level = "Data";
my $second_level = "Dumper";
print Dumper \%{${$::{$top_level."::"}}{$second_level."::"}};

use Data::Dumper;
my $top_level = "Data";
my $second_level = "Dumper";
my $subname = "Dumper";
print &{${${$::{$top_level."::"}}{$second_level."::"}}{$subname}}(\%Data::);