docs: public UserPoolClientType withCallbackURLs(String... callbackURLs) {
          if (this.callbackURLs == null) {
              setCallbackURLs(new java.util.ArrayList<String>(callbackURLs.length));
          }
          for (String ele : callbackURLs) {
              this.callbackURLs.add(ele);
          }
          return this;
      }