SMTP::__construct PHP Method

    public function __construct()
    {
        $this->smtp_conn = 0;
        $this->error = null;
        $this->helo_rply = null;
        $this->do_debug = 0;
    }

 /**
  * Direct invocation of the constructor is not permitted.
  */
 protected function __construct(array $config)
 {
     $config['smtp_host'] = 'smtp.sendgrid.net';
     $config['smtp_port'] = 465;
     $config['smtp_security'] = 'ssl';
     $config['smtp_user'] = $config['api_user'];
     $config['smtp_pass'] = $config['api_pass'];
     parent::__construct($config);
 }