Possible Magento garbage collection & cleanup

 
<?php
 
/**
 * Enter description here...
 *
 * @param string $field
 * @return boolean
 */
public function isDirty($field=null)
{
	if (empty($this->_dirty)) {
		return false;
	}
	if (is_null($field)) {
		return true;
	}
	return isset($this->_dirty[$field]);
}
 
/**
 * Enter description here...
 *
 * @param string $field
 * @param boolean $flag
 * @return Varien_Object
 */
public function flagDirty($field, $flag=true)
{
	if (is_null($field)) {
		foreach ($this->getData() as $field=>$value) {
			$this->flagDirty($field, $flag);
		}
	} else {
		if ($flag) {
			$this->_dirty[$field] = true;
		} else {
			unset($this->_dirty[$field]);
		}
	}
	return $this;
}
 
?>