code: function getThemeFiles({ brand, affiliate }) {
    return [
      path.join(__dirname, '/themes/_default.yaml'),
      path.join(__dirname, `/themes/${brand}/_default.yaml`),
      path.join(__dirname, `/themes/${brand}/${affiliate.toUpperCase()}/_default.yaml`)
    ].filter(fs.existsSync);
  }
docs: Get theme files in YAML format
  @param  {Object} options
  @param  {string} options.brand - cheaptickets
  @param  {string} options.affiliate - NL
  @return {String}