How to implement the Visitor design pattern in PHP for performing operations on a group of objects?

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interface Visitor {
  public function visitElementA(ElementA $elementA);
  public function visitElementB(ElementB $elementB);
}

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abstract class Element {
  public abstract function accept(Visitor $visitor);
}

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class ElementA extends Element {
  public function accept(Visitor $visitor) {
    $visitor->visitElementA($this);
  }
}

class ElementB extends Element {
  public function accept(Visitor $visitor) {
    $visitor->visitElementB($this);
  }
}

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class ConcreteVisitor implements Visitor {
  public function visitElementA(ElementA $elementA) {
    // Define the operation for ElementA
  }
  
  public function visitElementB(ElementB $elementB) {
    // Define the operation for ElementB
  }
}

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$elements = array(new ElementA(), new ElementB());
$visitor = new ConcreteVisitor();

foreach ($elements as $element) {
  $element->accept($visitor);
}