code: private String getThemeString(PageParameters parameters){
          String themeString = "default";
          if (parameters.getAllNamed().size() < 2) {
              return themeString;
          } else {
              themeString= parameters.getAllNamed().get(0).getValue();
          }
          return themeString;
      }
docs: Returns the name of the current theme from the page parameters
  @param parameters the page parameters from the page URI
  @return The name of the current theme