IndexError when using DataHandlerLP

[x7jeon8gi]

Hello,

I am encountering an UnsortedIndexError when using DataHandlerLP in Qlib. It seems to be related to MultiIndex not being lexsorted. Could you provide guidance on how to resolve this issue?

UnsortedIndexError: 'MultiIndex slicing requires the index to be lexsorted: slicing on levels [0], lexsort depth 0'

handler = DataHandlerLP(
    data_loader={
        "class": "QlibDataLoader",
        "kwargs": {
            "config": {
                "feature": market_info,
                "label": ["Ref($close, -2)/Ref($close, -1) - 1"]
            },
        }
    },
    instruments="csi300",
    infer_processors=[
        {
            "class": 'RobustZScoreNorm', 
            'kwargs': {
                'clip_outlier': True, 
                'fields_group': 'feature', 
                'fit_start_time': '2009-01-01', 
                'fit_end_time': '2019-12-31'
            }
        },
        {
            'class': 'Fillna', 
            'kwargs': {
                'fields_group': 'feature',
            }
        },
    ],
    learn_processors=[
        {"class": 'DropnaLabel'},
        {
            "class": 'CSZScoreNorm', 
            'kwargs': {
                'fields_group': 'label',
            }
        },
    ],

)

Thank you.