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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 get_optimized_symbol(executor):
 """ Take an executor's underlying symbol graph and return its generated optimized version. Parameters executor : An executor for which you want to see an optimized symbol. Getting an optimized symbol is useful to compare and verify the work TensorRT has done against a legacy behaviour. Returns ------- symbol : nnvm::Symbol The nnvm symbol optimized. """

    handle = SymbolHandle()
    try:
        check_call(_LIB.MXExecutorGetOptimizedSymbol(executor.handle, ctypes.byref(handle)))
        result = sym.Symbol(handle=handle)
        return result
    except MXNetError:
        logging.error('Error while trying to fetch TRT optimized symbol for graph. Please ensure '
                      'build was compiled with MXNET_USE_TENSORRT enabled.')
        raise