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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 visit_BinOp(self, node):
 """ Combine operands ranges for given operator. Interval(low=-1, high=-1) """

        res = combine(node.op, self.visit(node.left), self.visit(node.right))
        return self.add(node, res)