/**
* (PHP 5 >= 5.1.0)<br/>
* Move forward to next element
* @link http://php.net/manual/en/iterator.next.php
* @return void Any returned value is ignored.
*/
public function next()
{
if (null === $this->current) {
$this->current = new Month($this->begin);
} else {
$this->current = $this->current->getNext();
if (!$this->contains($this->current->getBegin())) {
$this->current = null;
}
}
}