'Get the PE-ID for list of group_ids
@param group_ids: the list of group_ids
@return: dictionary of pe_id and group_id'

def _get_group_pe_id(self, group_ids):

    if group_ids:
        gtable = current.s3db.pr_group
        rows = current.db(gtable.id.belongs(group_ids)).select(gtable.id, gtable.pe_id)
        if rows:
            return {row.pe_id: row.id for row in rows}
    return None
