A class method that is both a getter and a setter

ACDC.php

<?php

class ACDC {

  protected $_data = null;

  public function data()
  {
    $args = func_get_args();

    if (!empty($args)) {
      $this->_data = array_shift($args);
    }

    return $this->_data;

  }

}

$acdc = new ACDC();
$acdc->data('Hello World');
echo $acdc->data();