Inheritance in PHP

Boy.php

<?php
class Boy extends Person {
  public function washHands() {
    echo "I don't wash my hands...";
  }
}

inheritance.php

<?php
interface PersonInterface {
    public function eat($food);
}

interface BathroomInterface {
    public function poop();
    public function pee();
    public function washHands();
}

class Person implements PersonInterface, BathroomInterface {
    public $name;
    public $age;

    public function __construct($name, $age)
    {
        $this->name = $name;
        $this->age = $age;
    }

    public function eat($food) {
        echo $this->name . ' is eating ' . $food;
    }

    public function poop() {
        echo "I feel better.";
    }

    public function pee() {
        echo "Glad I didn't pee my pants";
    }

    public function washHands() {
        echo "Yes, I wash my hands.";
    }
}