code: public void unset(String propName) {
          if (propName.equals(PROP_VIEW_IDENTIFIERS)) {
              unsetViewIdentifiers();
          }
          if (propName.equals(PROP_CHILDREN)) {
              unsetChildren();
          }
          if (propName.equals(PROP_GROUPS)) {
              unsetGroups();
          }
  
          if (deletedProperties == null) {
              deletedProperties = new ArrayList();
          }
          deletedProperties.add(propName);
      }
docs: Sets the value of provided property to null.
  
  @param propName
  allowed object is {@link String}