<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def delete_group(group_id, purge_data,**kwargs):
 """ Remove group from DB completely If there are attributes on the group, use purge_data to try to delete the data. If no other resources group to this data, it will be deleted. """

    user_id = kwargs.get('user_id')
    try:
        group_i = db.DBSession.query(ResourceGroup).filter(ResourceGroup.id == group_id).one()
    except NoResultFound:
        raise ResourceNotFoundError("Group %s not found"%(group_id))

    group_items = db.DBSession.query(ResourceGroupItem).filter(
                                                    ResourceGroupItem.group_id==group_id).all()
    for gi in group_items:
        db.DBSession.delete(gi)

    if purge_data == 'Y':
        _purge_datasets_unique_to_resource('GROUP', group_id)

    log.info("Deleting group %s, id=%s", group_i.name, group_id)

    group_i.network.check_write_permission(user_id)
    db.DBSession.delete(group_i)
    db.DBSession.flush()