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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 _rewrite_where(self, q):
 """ Rewrite field names inside WHERE tree. """

        if isinstance(q, Lookup):
            self._rewrite_col(q.lhs)
        if isinstance(q, Node):
            for child in q.children:
                self._rewrite_where(child)