FeatureItem

{
    "feature_group": "compare",
    "items": [
        "合同比对"
    ],
    "used_cost": 6,
    "call_count": 1,
    "avail_call_count": 1968,
    "billing_mode": "per_call",
    "rate": 0.5,
    "unit_size": 1,
    "sub_features": [
        {
            "sub_feature": "compare-ocr",
            "rate": 6
        }
    ]
}