code: public void setRootToParentThingGroups(java.util.Collection<GroupNameAndArn> rootToParentThingGroups) {
          if (rootToParentThingGroups == null) {
              this.rootToParentThingGroups = null;
              return;
          }
  
          this.rootToParentThingGroups = new java.util.ArrayList<GroupNameAndArn>(rootToParentThingGroups);
      }
docs: <p>
  The root parent thing group.
  </p>
  
  @param rootToParentThingGroups
  The root parent thing group.