'Lookup all rows referenced by values.
@param key: the key Field
@param values: the values
@param fields: the fields to retrieve'

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

    if (not fields):
        table = self.table
        fields = [table[f] for f in self.fields]
    rows = self._lookup_rows(key, values, fields=fields)
    pe_ids = [row.pe_id for row in rows]
    current.s3db.pr_pentity_represent.bulk(pe_ids)
    return rows
