code: protected final boolean isGroupNameValid(String name) {
          if (name == null) {
              return false;
          }
  
          if (!name.startsWith(DuracloudGroup.PREFIX)) {
              return false;
          }
  
          if (DuracloudGroup.PUBLIC_GROUP_NAME.equalsIgnoreCase(name)) {
              return false;
          }
  
          return name.substring(DuracloudGroup.PREFIX.length()).matches(
              "\\A(?![_.@\\-])[a-z0-9_.@\\-]+(?<![_.@\\-])\\Z");
      }
docs: This method is 'protected' for testing purposes only.