use strict;
use warnings;
use 5.012;

package Dog;

sub new {
    my $class = shift;
    my $self = {};
    bless $self, $class;
}

sub bark {
    say 'woof';
}

sub do_math {
    say '2 + 2 = 4';
}




package main;

sub func1 {
    my $obj = shift;
    $obj->do_math();
}

sub func2 {
    my $obj = shift;
    $obj->bark();
    func1($obj);
}

my $dog = Dog->new();
func2($dog);

--output:--
woof
2 + 2 = 4