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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 _prepare_header_cells(self, table_header):
 """ Set the scope of header cells of table header. :param table_header: The table header. :type table_header: hatemile.util.html.htmldomelement.HTMLDOMElement """


        cells = self.parser.find(table_header).find_children(
            'tr'
        ).find_children('th').list_results()
        for cell in cells:
            self.id_generator.generate_id(cell)

            cell.set_attribute('scope', 'col')