Argument of type is not assigned to the local notification

This is my code

this.platform.ready().then(() => {
      this.localNotifications.schedule({    // ionic local notification native plugin.
        title: 'Welcome',
        text: 'xxxxxxxxxx',
        at: new Date(new Date().getTime() + 1000)

When use the at variable i get the error as

Argument of type ‘{ title: any; text: string; at: Date; }’ is not assignable to parameter of type ‘ILocalNotification | ILocalNotification’.
Object literal may only specify known properties, and ‘at’ does not exist in type ‘ILocalNotification | ILocalNotification’.

I want to prompt the notification after 1 sec. How can I do it ?