ccxt: okex future, can not change lever_rate to 20 when creating order

when I create new order, I can change contract type by pass the contract type in the ‘params’, but lever_rate is always default to 10, can not change to 20 if I simply pass ‘lever_rate’: 20 to the params

async function run () {
  await fure.createOrder('BTC/USD', 'limit', 1, 1, 5000, {'contract_type': 'next_week', 'lever_rate': 20})
}

run()

this is a simple version of my code function: createOrder: Exchange: okex method: POST ccxt version: 1.16.32

Issue: placed order of next week but lever_rate is 10, should be 20