code: function Pass(template, fields, images) {
    this.template = template;
    this.fields = cloneObject(fields);
    // Structure is basically reference to all the fields under a given style
    // key, e.g. if style is coupon then structure.primaryFields maps to
    // fields.coupon.primaryFields.
    var style = template.style;
    this.structure = this.fields[style];
    if (!this.structure)
      this.structure = this.fields[style] = {};
    this.images = cloneObject(images);
  }
docs: Create a new pass.  template  - The template fields    - Pass fields (description, serialNumber, logoText)