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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 _on_delete(self, builder):
 """ The delete replacement function. :param builder: The query builder :type builder: orator.orm.builder.Builder """

        column = self._get_deleted_at_column(builder)

        return builder.update({column: builder.get_model().fresh_timestamp()})