I am new to safari web push notification, I have created pushpackage for safari and, I have placed javascript code to get user notification confirmation but Getting issue i.e TypeError: checkRemotePermission is not a function. (In 'checkRemotePermission(permissionData)', 'checkRemotePermission' is undefined)

My code

if ('safari' in window && 'pushNotification' in window.safari) {
    var permissionData = window.safari.pushNotification.permission('web.in.test.website');
    console.log("safari " + permissionData.permission);
    checkRemotePermission(permissionData);
}


var checkRemotePermission =  function(permissionData) {
    if (permissionData.permission === 'default') {
        // This is a new web service URL and its validity is unknown.
        window.safari.pushNotification.requestPermission(
            'https://testsite.com', // The web service URL.
            ''web.in.test.website',     // The Website Push ID.
            {},         // Data used to help you identify the user.
            checkRemotePermission         // The callback function.
        );
    }
    else if (permissionData.permission === 'denied') {
      // The user said no. Talk to your UX expert to see what you can do to entice your
      // users to subscribe to push notifications.
      console.log(permissionData.permission);
    }
    else if (permissionData.permission === 'granted') {
        // The web service URL is a valid push provider, and the user said yes.
        // permissionData.deviceToken is now available to use.
        console.log(permissionData.permission);
        console.log(permissionData.deviceToken);
    } 
}

Please help me thanks in advance