code: private void checkEditResourceNotSet() throws CmsUgcException {
  
          if (m_editResource != null) {
              String message = Messages.get().container(Messages.ERR_CANT_EDIT_MULTIPLE_CONTENTS_IN_SESSION_0).key(
                  getCmsObject().getRequestContext().getLocale());
              throw new CmsUgcException(CmsUgcConstants.ErrorCode.errInvalidAction, message);
  
          }
      }
docs: Throws an error if the edit resource is already set.<p>
  
  @throws CmsUgcException if the edit resource is already set