docs: function funnel (arr, valueFieldName, labelFieldName) {
    // geckboard funnel holds a maximum of 8 items
    if (arr.length > 8) {
      arr = arr.slice(0,8);
    }
  
    var steps = [];
    for (var i = 0; i < arr.length; i++) {
      var step = {
        "value": arr[i][valueFieldName],
        "label": arr[i][labelFieldName]
      };
      steps.push(step);
    }
    var output = {
      "item": steps
    };
    return output;
  }