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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 order_by(self, *field_names):
 """ Mark the filter as being ordered if search has occurred. """

        if not self._search_ordered:
            self._search_ordered = len(self._search_terms) > 0
        return super(SearchableQuerySet, self).order_by(*field_names)