public function deleteBy($condition = null)
	{
		if( !is_null($condition) )
		{
			$this->filterBy($condition);
		}
		$matched = $this->load();
		array_each(
			$matched,
			function($model)
			{ /** @var Lib_Model_Db $model */
				$model->delete();
			}
		);
		return !empty($matched);
	}