lets elaborate, in the following code you can see a simplified standard Perl class with private and public variables and methods.

The private data is only visible and accessible within the methods because of Perl's closure mechanism.

{
  package TEST_CLASS;
  
  my $private_class_var;
  our $public_class_var;

  my $private_method =
    sub {
      my ($self,@args)=@_;
      print "-- private_method(@args)\n";
    };

  sub public_method {
    my ($self,@args)=@_;
    print "- public_method(@args)\n";
    
    $self->$private_method(7..9);
  }

  sub new {
    my ($class,%args)=@_;
    bless \%args, $class;
    return \%args;
  }
}

my $obj = TEST_CLASS->new(a=>1,b=>2);

$obj->public_method(1..3);
$obj->private_method(4..6);
[download]

prints

- public_method(1 2 3)
-- private_method(7 8 9)
Can't locate object method "private_method" via package "TEST_CLASS" a
+t /tmp/tst_pkg.pl line 32.
[download]

So, does this count as real life example?