diff --git a/src/totp.js b/src/totp.js
index 2f0eeb2..085630a 100644
--- a/src/totp.js
+++ b/src/totp.js
@@ -14,8 +14,8 @@ import OTP from './otp';
      *
      * @return {OTP}
      */
-    constructor(interval=30, ...args) {
-        super(...args);
+    constructor(secret, interval=30) {
+        super(secret);
         this.interval = interval;
     }