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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 _buildTerms(self):
 """ Builds a data structure indexing the terms longitude by sign and object. """

        termLons = tables.termLons(tables.EGYPTIAN_TERMS)
        res = {}
        for (ID, sign, lon) in termLons:
            try:
                res[sign][ID] = lon
            except KeyError:
                res[sign] = {}
                res[sign][ID] = lon
        return res