code: function (productTypes) {
  
              var colorHash,
                  ret = [];
              productTypes.each(function (productType) {
                  colorHash = productTypeToColorMap[productType.$.id];
                  for (var color in colorHash) {
                      if (colorHash.hasOwnProperty(color) && (ret.indexOf(colorMap[color]) === -1)) {
                          ret.push(colorMap[color]);
                      }
                  }
              });
  
              return ret;
          }
docs: *
  Returns a Array of color strings for a js.core.List of productTypes
  @param {js.core.List} productTypes
  @returns {Array}