docs: @Override
      public boolean getIsEmptyOrWhitespaceOnly() {
  
          if (m_contentValue == null) {
              // this is the case for non existing values
              return true;
          }
          if (m_contentValue.isSimpleType()) {
              // return values for simple type
              return CmsStringUtil.isEmptyOrWhitespaceOnly(m_contentValue.getStringValue(m_cms));
          } else {
              // nested types are not empty if they have any children in the XML
              return m_contentValue.getElement().elements().isEmpty();
          }
      }