code: public static PactDslJsonRootValue ipAddress() {
      PactDslJsonRootValue value = new PactDslJsonRootValue();
      value.setValue("127.0.0.1");
      value.setMatcher(value.regexp("(\\d{1,3}\\.)+\\d{1,3}"));
      return value;
    }
docs: Value that must be an IP4 address