这个步骤的功能是啥

public static function init() {
	    // config info
	    global $setting_config;
	    self::parse_conf($setting_config);
	    define('MD5_KEY',md5($setting_config['md5_key']));

	    if(function_exists('date_default_timezone_set')){
	        if (is_numeric($setting_config['time_zone'])){
	            @date_default_timezone_set('Asia/Shanghai');
	        }else{
	            @date_default_timezone_set($setting_config['time_zone']);
	        }
	    }

	    //session start
	    self::start_session();
	    
	    //output to the template
	    Tpl::output('setting_config',$setting_config);
	    
	    //read language
	    Language::read('core_lang_index');
	}