get child attr

#html file

<dom-module id="year-view">
    <style>
    paper-card {
      margin-bottom: 20px;
      }
    </style>
  <template>

    <iron-ajax
    auto
    url="{{url}}"
    handle-as="json"
    last-response="{{response}}">
    </iron-ajax>

    <template is="dom-repeat" items="[[response]]">
        <div  class="col-xs-6 col-sm-3">
            <paper-card image="[[item.chapters.0.data.thumbnails]]" >
                <month-name the-month="[[item.latest_date]]"></month-name>
                <div class="catebox">
                    <template is="dom-repeat" items="[[item.categories]]">
                        <category-color the-cateid="[[item]]" ></category-color>
                    </template>
                </div>
            </paper-card>
        </div>
    </template>

  </template>

  <script src="year-view.js"></script>
</dom-module>

#js file
(function() {
  'use strict';

  Polymer({
    is: 'year-view',
    listeners: {
        'tap': 'regularTap'
    },
    properties:{
      theYear:{
        reflectToAttribute: true,
        type:String
      },
      url:{
        computed: 'computeUrl(theYear)'
      }

    },

    computeUrl: function(theYear){
      return ['/api/calendar',theYear].join('/');
    },
    regularTap:function(e){
      alert("Hmmmm "+this.theCateid);
    }

  });

})();