'Custom rows lookup
@param key: the key Field
@param values: the values
@param fields: unused (retained for API compatibility)'

def lookup_rows(self, key, values, fields=[]):

    table = current.s3db.dvr_activity
    count = len(values)
    if (count == 1):
        query = (key == values[0])
    else:
        query = key.belongs(values)
    rows = current.db(query).select(table.id, table.name, table.start_date, table.end_date, table.service_id, table.facilitator, limitby=(0, count))
    self.queries += 1
    services = set()
    for row in rows:
        service_id = row.service_id
        if service_id:
            services.add(service_id)
    if services:
        represent = table.service_id.represent
        represent.bulk(list(services))
    return rows
