class Person { private $nickname; private $year_of_birth; private $gender; public function __construct ($nickname, $year_of_birth, $gender) { $this-> nickname = $nickname; $this -> year_of_birth = $year_of_birth; $this ->gender = $gender; } public function get_nickname(){ return $this->nickname; } public function get_year(){ return $this->year; } public function get_gender(){ return $this->gender; } public function calculate_age(){ return date('Y') - $this->year_of_birth; } } ?>