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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 benchmark_backward(self):
 """Benchmark backward execution. Note: If backward execution throws any exception, this benchmark system considers the error is because the function doesn't support backward operation, then set the benchmark ``None``. """

        try:
            self._benchmark_backward()
        except RuntimeError as e:
            # Seems like not implemented.
            print(e)
            self.mod_ext.synchronize(**self.ext_kwargs)
            self.backward_stat = None