src/transformers/models/maskformer/convert_maskformer_resnet_to_pytorch.py/convert_maskformer_checkpoint
def convert_maskformer_checkpoint(
    model_name: str, checkpoint_path: str, pytorch_dump_folder_path: str, push_to_hub: bool = False
):
    """
    Copy/paste/tweak model's weights to our MaskFormer structure.
    """
    config = get_maskformer_config(model_name)

    # load original state_dict
    with open(checkpoint_path, "rb") as f:
        data = pickle.load(f)
    state_dict = data["model"]

    # rename keys
    rename_keys = create_rename_keys(config)
    for src, dest in rename_keys:
        rename_key(state_dict, src, dest)
    read_in_decoder_q_k_v(state_dict, config)

    # update to torch tensors
    for key, value in state_dict.items():
        state_dict[key] = torch.from_numpy(value)

    # load 🤗 model
    model = MaskFormerForInstanceSegmentation(config)
    model.eval()

    model.load_state_dict(state_dict)

    # verify results
    image = prepare_img()
    if "vistas" in model_name:
        ignore_index = 65
    elif "cityscapes" in model_name:
        ignore_index = 65535
    else:
        ignore_index = 255
    reduce_labels = True if "ade" in model_name else False
    feature_extractor = MaskFormerFeatureExtractor(ignore_index=ignore_index, reduce_labels=reduce_labels)

    inputs = feature_extractor(image, return_tensors="pt")

    outputs = model(**inputs)

    if model_name == "maskformer-resnet50-ade":
        expected_logits = torch.tensor(
            [[6.7710, -0.1452, -3.5687], [1.9165, -1.0010, -1.8614], [3.6209, -0.2950, -1.3813]]
        )
    elif model_name == "maskformer-resnet101-ade":
        expected_logits = torch.tensor(
            [[4.0381, -1.1483, -1.9688], [2.7083, -1.9147, -2.2555], [3.4367, -1.3711, -2.1609]]
        )
    elif model_name == "maskformer-resnet50-coco-stuff":
        expected_logits = torch.tensor(
            [[3.2309, -3.0481, -2.8695], [5.4986, -5.4242, -2.4211], [6.2100, -5.2279, -2.7786]]
        )
    elif model_name == "maskformer-resnet101-coco-stuff":
        expected_logits = torch.tensor(
            [[4.7188, -3.2585, -2.8857], [6.6871, -2.9181, -1.2487], [7.2449, -2.2764, -2.1874]]
        )
    elif model_name == "maskformer-resnet101-cityscapes":
        expected_logits = torch.tensor(
            [[-1.8861, -1.5465, 0.6749], [-2.3677, -1.6707, -0.0867], [-2.2314, -1.9530, -0.9132]]
        )
    elif model_name == "maskformer-resnet50-vistas":
        expected_logits = torch.tensor(
            [[-6.3917, -1.5216, -1.1392], [-5.5335, -4.5318, -1.8339], [-4.3576, -4.0301, 0.2162]]
        )
    elif model_name == "maskformer-resnet50-ade20k-full":
        expected_logits = torch.tensor(
            [[3.6146, -1.9367, -3.2534], [4.0099, 0.2027, -2.7576], [3.3913, -2.3644, -3.9519]]
        )
    elif model_name == "maskformer-resnet101-ade20k-full":
        expected_logits = torch.tensor(
            [[3.2211, -1.6550, -2.7605], [2.8559, -2.4512, -2.9574], [2.6331, -2.6775, -2.1844]]
        )

    assert torch.allclose(outputs.class_queries_logits[0, :3, :3], expected_logits, atol=1e-4)
    print("Looks ok!")

    if pytorch_dump_folder_path is not None:
        print(f"Saving model and feature extractor of {model_name} to {pytorch_dump_folder_path}")
        Path(pytorch_dump_folder_path).mkdir(exist_ok=True)
        model.save_pretrained(pytorch_dump_folder_path)
        feature_extractor.save_pretrained(pytorch_dump_folder_path)

    if push_to_hub:
        print(f"Pushing model and feature extractor of {model_name} to the hub...")
        model.push_to_hub(f"facebook/{model_name}")
        feature_extractor.push_to_hub(f"facebook/{model_name}")