package Foo {
    ...
    my @stuff = ( ... );  # initialized upon inclusion
    ...
    my $private_function = sub { ... };
    ...
    my $private_class_method  = sub { my $class   = shift;  ...; };
    my $private_object_method = sub { my $obj_ref = shift;  ...; };
    ...
    $private_function->(@stuff);
    ...
    $class_name->$private_class_method(...);
    $object_reference->$private_object_method(...);
    ...
    }