public static function validate($value)
    {
        assert(is_string($value));

        if ($value !== self::LAST && $value !== self::ERROR) {
            throw new ClientException('Invalid update policy');
        }
    }
public static function validate($value)
    {
        assert(is_string($value));

        if ($value !== self::LAST && $value !== self::ERROR) {
            throw new ClientException('Invalid update policy');
        }
    }
public static function validate ( $ value ) { assert ( is_string ( $ value ) ) ; if ( $ value !== self :: LAST && $ value !== self :: ERROR ) { throw new ClientException ( 'Invalid update policy' ) ; } }
Check if the supplied policy value is valid

@throws ClientException

@param string $value - update policy value

@return void
Check if the supplied policy value is valid