Compiling scriptmodel with tensorRT?

How can I compile scripted module with TensorRT?
I read this pytorch docs Using Torch-TensorRT Directly From PyTorch — Torch-TensorRT master documentation
and followed the instruction.

made the script_model using torch.jit.script
and put the same spec to

spec = {
    "forward":
        torch_tensorrt.ts.TensorRTCompileSpec({
            "inputs": [torch_tensorrt.Input([1, 3, 300, 300])],
            "enabled_precisions": {torch.float, torch.half},
            "refit": False,
            "debug": False,
            "device": {
                "device_type": torch_tensorrt.DeviceType.GPU,
                "gpu_id": 0,
                "dla_core": 0,
                "allow_gpu_fallback": True
            },
            "capability": torch_tensorrt.EngineCapability.default,
            "num_min_timing_iters": 2,
            "num_avg_timing_iters": 1,
        })
    }
trt_model = torch._C._jit_to_backend("tensorrt", script_model, spec) 

However, it made the input type error.
Input should have received that torch_tensorrt.Input but it received the whole dictionary as input. So I changed the dictionary format into

    spec = {
        "forward":
            torch_tensorrt.ts.TensorRTCompileSpec(
                inputs = [torch_tensorrt.Input((10,1,19,500))],
                enabled_precisions = {torch.float},
                refit = False,
                debug = False,
                device = {
                    "device_type": torch_tensorrt.DeviceType.GPU,
                    "gpu_id": 0,
                    "dla_core": 0,
                    "allow_gpu_fallback": True
                },
                capability = torch_tensorrt.EngineCapability.default,
                num_min_timing_iters= 2,
                num_avg_timing_iters= 1,
            )
        }

and now torch_tensorrt.ts.TensorRTCompileSpec function could read input well.
However, still it gives the following error.

trt_model = torch._C._jit_to_backend("tensorrt", model, spec)
RuntimeError: [Error thrown at /workspace/Torch-TensorRT/py/torch_tensorrt/csrc/tensorrt_backend.cpp:69] Expected core::CheckMethodOperatorSupport(mod, it->key().toStringRef()) to be true but got false
Method forwardcannot be compiled by Torch-TensorRT

I am following the tutorial docs and checked that the model was scripted well.
How can I solve this problem?
Also, when I tried to convert the pytorch model with torch_tensorrt.compile() directly.
It made segmentation fault error.