exit(1);
} else {
    Aerospike::setDeserializer(function ($val) {
        $prefix = substr($val, 0, 3);
        if ($prefix !== 'r||') {
            return unserialize(substr($val, 3));
        }
        return unserialize(substr($val, 3));
    });
    Aerospike::setSerializer(function ($val) {
        if (is_bool($val)) {
            return "b||" . serialize($val);
        }
        if (is_object($val)) {
            return "o||" . serialize($val);
        }
        if (is_double($val)) {
            return "d||" . serialize($val);
        }
        // otherwise, mark it as raw
        return "r||" . $val;
    });
    class edu_course
    {
        public $course_name;
        public $duration;
        function __construct($name, $years)
        {
            $this->course_name = $name;
            $this->duration = $years;
        }