Mediator Design Pattern: is this a correct implementation?

I'm learning and try to practice design patterns, I was trying to implement the mediator pattern based on this explanation, The code works as I wanted to do it, but as I changed a few things and implemented methods and classes inside the concrete class, I don't know if the pattern is correctly implemented, can you please comment on this.

<?php 

namespace DesignPatternsPractice\Mediator;

interface Mediator 
{
    public function notify(object $sender, string $event);
}

class ConcreteMediator implements Mediator {
    private $component;

    public function __construct($component) {
        $this->component = $component;
        $this->component->setMediator($this);
        $this->family = new Family();
        $this->family->setMediator($this);
    }

    public function notify($sender, $event) {
        if($sender instanceof Kidnapper && $event === "called_family") {
            echo "The family suspected a kidnapping, didn't responded the call and called a mediator \n";
            $this->family->callMediator();
        } else if($sender instanceof Kidnapper && $event === "called_mediator") {
            $this->callFamily();
        }

        if ($sender instanceof Family && $event === "called_mediator") {
            echo "Mediator is ready to respond the new call from the kidnapper\n";
        }

        if($sender instanceof ConcreteMediator && $event === "called_police") {
            echo "The police does not negotiates with kidnappers and the victim was rescued \n";
        }
    }

    public function callFamily() {
        echo "The family responded no to the demands and tell the mediator to call the police \n";
        $this->callPolice();
    }

    public function callPolice() {
        $this->notify($this, "called_police");
    }
}

class BaseComponent {
    protected $mediator;

    public function __construct(Mediator $mediator = null)
    {
        $this->mediator = $mediator;
    }

    public function setMediator(Mediator $mediator): void
    {
        $this->mediator = $mediator;
    }
}

class Kidnapper extends BaseComponent {
    
    public function callFamily() {
        $this->mediator->notify($this, "called_family");
    }

    public function callMediator() {
        echo "Mediator asked for demands\n";
        $this->mediator->notify($this, "called_mediator");
    }
}

class Family extends BaseComponent {    
    public function callMediator() {
        $this->mediator->notify($this, "called_mediator");
    }
}

$kn = new Kidnapper();
$mediator = new ConcreteMediator($kn);
$kn->callFamily();
$kn->callMediator();