Magento - create entity if doesnt exist

createIfDoesntExist.php

    /**
     * Load object data and create if doesnt exist
     *
     * @param   integer $id
     * @return  Mage_Core_Model_Abstract
     */
    public function createIfDoesntExist($id, $field=null)
    {
        $this->load($id, $field);
        if(!$this->getId()){
            $this->setData($field, $id);
            $this->save();
        }
        return $this;
    }