class User { private $name; private $email; private $gender; public function setGender($gender) { $this->gender = $gender; // Update gender in database } } $user = new User(); $user->setGender('male');In this example, we create a User class with private properties for name, email, and gender. The setGender function is a public method that updates the gender property and also updates the gender in the database. Package library: There are no specific package libraries required for the setGender function as it can be implemented using basic PHP functions and database queries. However, if you are using a web framework like Laravel or CodeIgniter, they may have their own built-in functions for setting user gender.