gapitoken: token undefined issue

gapitoken-test.js

var util = require('util');
var GAPI = require('gapitoken');

var gapi = new GAPI({
  iss: '1074036960964-p8827i23hcprb8dr959uh2a6irk1jgfe@developer.gserviceaccount.com',
  scope: 'https://storage.googleapis.com',
  keyFile: './config/google-key.pem'
}, function(error){
  console.log(error);
  console.log(gapi);
  gapi.getToken(function(error, token){
    console.log(error);
    console.log(token);
    console.log(gapi);
  });
});

console.log(gapi);

google-key.pem

-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

the scope is incorrect, use https://www.googleapis.com/auth/devstorage.full_control