Ember Sign-up CreateUser not a function

I am trying to create a user on ember with Firebase for the backend. Here is my code on my sign-up controller:

import Ember from 'ember';

export default Ember.Controller.extend({  
  firebase: Ember.inject.service(),
  actions: {
    signUp() {
        let controller = this;
        var email = this.get('email');
        var password = this.get('password');
        this.get('firebase').createUserWithEmailAndPassword(email, password).catch(function(error) {
            var errorCode = error.code;
            console.log(errorCode);
            var errorMessage = error.message;
            console.log(errorMessage);
        });
    }
  }
});

currently getting the error that createUserWithEmailAndPassword is not a functionHere is a screenshot of the error Thank you.