docs: public static Filter createFilterFromFilterSpec(Request request, String filterSpec)
              throws FilterFactory.FilterNotCreatedException {
          Description topLevelDescription = request.getRunner().getDescription();
          String[] tuple;
  
          if (filterSpec.contains("=")) {
              tuple = filterSpec.split("=", 2);
          } else {
              tuple = new String[]{ filterSpec, "" };
          }
  
          return createFilter(tuple[0], new FilterFactoryParams(topLevelDescription, tuple[1]));
      }