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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 _sortAttributeValue(self, offset):
 """ return the value of the sort attribute for the item at 'offset' in the results of the last query, otherwise None. """

        if self._currentResults:
            pageStart = (self._currentResults[offset][
                self.currentSortColumn.attributeID],
                         self._currentResults[offset][
                    '__item__'].storeID)
        else:
            pageStart = None
        return pageStart