original_string: public static function instance($model_class)
  	{
  		$observer = get_called_class();
  		if (empty(static::$_instances[$observer][$model_class]))
  		{
  			static::$_instances[$observer][$model_class] = new static($model_class);
  		}
  
  		return static::$_instances[$observer][$model_class];
  	}
code: public static function instance($model_class)
  	{
  		$observer = get_called_class();
  		if (empty(static::$_instances[$observer][$model_class]))
  		{
  			static::$_instances[$observer][$model_class] = new static($model_class);
  		}
  
  		return static::$_instances[$observer][$model_class];
  	}
code_tokens: public static function instance ( $ model_class ) { $ observer = get_called_class ( ) ; if ( empty ( static :: $ _instances [ $ observer ] [ $ model_class ] ) ) { static :: $ _instances [ $ observer ] [ $ model_class ] = new static ( $ model_class ) ; } return static :: $ _instances [ $ observer ] [ $ model_class ] ; }
docstring: Create an instance of this observer
  
  @param  string  name of the model class
docstring_tokens: Create an instance of this observer