{
    "num_leaves": {
        "_type": "randint",
        "_value": [20, 31]
    },
    "learning_rate": {
        "_type": "choice",
        "_value": [0.01, 0.05, 0.1, 0.2]
    },
    "bagging_fraction": {
        "_type": "uniform",
        "_value": [0.7, 1.0]
    },
    "bagging_freq": {
        "_type": "choice",
        "_value": [1, 2, 4, 8, 10]
    }
}