'Get the UUIDs of all records currently stored in this instance'

def get_uid(self):

    if (current.xml.UID not in self.table.fields):
        return None
    if (self._ids is None):
        self.__load_ids()
    if (not self._uids):
        return None
    elif (len(self._uids) == 1):
        return self._uids[0]
    else:
        return self._uids
