docs: def delete_attribute_group(group_id, **kwargs):
      """
          Delete an attribute group.
      """
      user_id = kwargs['user_id']
  
      try:
  
          group_i = db.DBSession.query(AttrGroup).filter(AttrGroup.id==group_id).one()
  
          group_i.project.check_write_permission(user_id)
  
          db.DBSession.delete(group_i)
          db.DBSession.flush()
  
          log.info("Group %s in project %s deleted", group_i.id, group_i.project_id)
      except NoResultFound:
  
          raise HydraError('No Attribute Group %s was found', group_id)
  
  
      return 'OK'