public function normalizeValue($value)
	{
		if ($value instanceof AttributeFilter)
		{
			return $value;
		}

		if (is_callable($value))
		{
			return new AttributeFilter($value);
		}

		throw new InvalidArgumentException('Argument 1 passed to ' . __METHOD__ . ' must be a valid callback or an instance of s9e\\TextFormatter\\Configurator\\Items\\AttributeFilter');
	}