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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 addVariantSet(self, variantSet):
 """ Adds the specified variantSet to this dataset. """

        id_ = variantSet.getId()
        self._variantSetIdMap[id_] = variantSet
        self._variantSetNameMap[variantSet.getLocalId()] = variantSet
        self._variantSetIds.append(id_)