/**
     * Delete a Content Type Group.
     *
     * This method only deletes an content type group which has content types without any content instances
     *
     * @throws \eZ\Publish\API\Repository\Exceptions\UnauthorizedException if the user is not allowed to delete a content type group
     * @throws \eZ\Publish\API\Repository\Exceptions\InvalidArgumentException If  a to be deleted content type has instances
     *
     * @param \eZ\Publish\API\Repository\Values\ContentType\ContentTypeGroup $contentTypeGroup
     */
    public function deleteContentTypeGroup( APIContentTypeGroup $contentTypeGroup )
    {
        if ( $this->repository->hasAccess( 'class', 'delete' ) !== true )
            throw new UnauthorizedException( 'ContentType', 'delete' );

        $loadedContentTypeGroup = $this->loadContentTypeGroup( $contentTypeGroup->id );

        $this->repository->beginTransaction();
        try
        {
            $this->contentTypeHandler->deleteGroup(
                $loadedContentTypeGroup->id
            );
            $this->repository->commit();
        }
        catch ( APIBadStateException $e )
        {
            $this->repository->rollback();
            throw new InvalidArgumentException(
                "\$contentTypeGroup",
                "Content type group has content type instances",
                $e
            );
        }
        catch ( Exception $e )
        {
            $this->repository->rollback();
            throw $e;
        }
    }
 /**
  * @param mixed $groupId
  * @throws \eZ\Publish\API\Repository\Exceptions\BadStateException If type group contains types
  * @throws \eZ\Publish\API\Repository\Exceptions\NotFoundException If type group with id is not found
  */
 public function deleteGroup($groupId)
 {
     $this->clearCache();
     return $this->innerHandler->deleteGroup($groupId);
 }