Андрей

<?php
class a {
    public $a = 1;
    public $b = 2;
}
$obj = new a();
foreach ($obj as $value) {
    echo $value.'|';
}
//1|2
?>

<?php
class MyIterator implements Iterator
{
    private $var = array();

    public function __construct($array)
    {
        if (is_array($array)) {
            $this->var = $array;
        }
    }

    public function rewind()
    {
        echo "перемотка в начало\n";
        reset($this->var);
    }
  
    public function current()
    {
        $var = current($this->var);
        echo "текущий: $var\n";
        return $var;
    }
  
    public function key() 
    {
        $var = key($this->var);
        echo "ключ: $var\n";
        return $var;
    }
  
    public function next() 
    {
        $var = next($this->var);
        echo "следующий: $var\n";
        return $var;
    }
  
    public function valid()
    {
        $key = key($this->var);
        $var = ($key !== NULL && $key !== FALSE);
        echo "верный: $var\n";
        return $var;
    }

}

$values = array(1,2,3);
$it = new MyIterator($values);

foreach ($it as $a => $b) {
    print "$a: $b\n";
}
?>

$notifier = new Notifier(new Sms());
$notifier->send ....

$notifier = new Notifier(new Mail());
$notifier->send....

$config['bootstrap'][] = 'debug';
    $config['modules']['debug'] = [
        'class' => 'yii\debug\Module',
        'allowedIPs' => ['*'],
    ];
    $config['bootstrap'][] = 'gii';
    $config['modules']['gii'] = [
        'class' => 'yii\gii\Module',
        'allowedIPs' => ['*'],
    ];

['role', 'required'],
['role', 'in', 'range' => ['admin', 'distributor', 'reseller', 'customer'], 'message' => 'Wrong Rule'],

public function init() {
    $this->getUsers();
    parent::init();
}