Push.on() not define in phonegap.plugin.push

I followed this (https://docs.ionic.io/services/push/) tutorial and stuck in here.
When I try to call push.on() it gives build error. IDE also show there is no method called “on()”

push.on(‘notification’, function(data) {
// do something with the push data
// then call finish to let the OS know we are done
push.finish(function() {
console.log(“processing of push data is finished”);
}, function() {
console.log("something went wrong with push.finish for ID = " + data.additionalData.notId)
}, data.additionalData.notId);

Please help me!!