code: private String createID(String facetTitleNormalised) {
          facetTitleNormalised = facetTitleNormalised.replaceAll("\\W", "_"); //replace non word characters ie [a-zA-Z_0-9]
          facetTitleNormalised = facetTitleNormalised.replaceAll("\\-", "_"); //replace non word characters ie [a-zA-Z_0-9]
          facetTitleNormalised = facetTitleNormalised.replaceAll("\\s", "_"); //replace non word characters ie [a-zA-Z_0-9]
          facetTitleNormalised = facetTitleNormalised.toLowerCase(); //replace non word characters ie [a-zA-Z_0-9]
          return "facetID" + facetTitleNormalised;
      }
docs: ID and NAME tokens must begin with a letter ([A-Za-z]) and may be followed by any number of letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), and periods (".").
  
  @param facetTitleNormalised
  @return