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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 add_index(self, attribute, ordered=False):
 """ Adds an index to this map for the specified entries so that queries can run faster. Example: Let's say your map values are Employee objects. If you query your values mostly based on age and active fields, you should consider indexing these. :param attribute: (str), index attribute of the value. :param ordered: (bool), for ordering the index or not (optional). """

        return self._encode_invoke(map_add_index_codec, attribute=attribute, ordered=ordered)