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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def ids(self):
 """A list of unique IDs used to identify a row. If not explicitly set, it defaults to the first column name. """

        if self._ids is None:
            if self._columns:
                if isinstance(self._columns, OrderedDict):
                    return [list(self._columns.keys())[0]]
                return [self._columns[0]]
        else:
            return self._ids