code: public void generateSingleOffering(String offeringNodeTemplates) {
          this.removeOffering("0");
          Offering singleOffering = new Offering("all");
          singleOffering.toscaString = offeringNodeTemplates;
          this.addOffering(singleOffering);
      }
docs: Generates a single offering file containing all node templates fetched
  
  @param offeringNodeTemplates node templates to write on file