iron-ajax can not find generateRequest()-Method

I am new to Polymer and try to create an ajax call by iron-ajax. I run into an error, that generateRequest()is undefined.

Polymer 1 is in use.

I installed iron-ajax with this command: bower install --save PolymerLabs/promise-polyfill#1

And as you can see, I load it with <link rel="import" href="../bower_components/promise-polyfill/promise-polyfill-lite.html">

I compare it with some examples but can not find the mistake. Does someone has an idea or solution?

this is the code:

<!--
@license
Copyright (c) 2016 The Polymer Project Authors. All rights reserved.
This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
Code distributed by Google as part of the polymer project is also
subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
-->

<link rel="import" href="../bower_components/polymer/polymer.html">
<link rel="import" href="shared-styles.html">
<link rel="import" href="../bower_components/promise-polyfill/promise-polyfill-lite.html">
<dom-module id="my-view2">
  <template>
    <style include="shared-styles">
      :host {
        display: block;

        padding: 10px;
      }
    </style>

    <div class="card">
      <div class="circle">2</div>
      <h1>View Two</h1>
      <p>Demo output</p>
    </div>

    <template is="dom-repeat" items="[[repos]]">
      <span>{{items.name}}</span>
    </template>
    <button on-click="setajax">Click me</button>

    <iron-ajax
            id="ajax"
            url=""
            params='{"type":"all"}'
            handle-as="json"
            on-response="hresponse"
            debounce-duration="300" >
    </iron-ajax>
  </template>

  <script>
    Polymer({
      is: 'my-view2',
        setajax: function () {
            this.$.ajax.url = "https://api.github.com/users/burczu/repos";
            this.$.ajax.params= {"type":"all"};
            this.$.ajax.generateRequest();
      },
        hresponse: function(request) {
            console.log(request.detail.response);
            console.log(this.$.ajax.lastResponse);
        }
    });
  </script>
</dom-module>

You need to install iron-ajax:

bower install --save PolymerElements/iron-ajax

Then, you can import using the following code:

<link rel="import" href="../bower_components/iron-ajax/iron-ajax.html">

Your code will work after you do the above things.