Cannot read property 'size' of undefined

[stimka]

const web3ws = new Web3(new Web3.providers.WebsocketProvider('ws://localhost:63116'));
await web3ws.eth.subscribe('newBlockHeaders');
await web3ws.eth.clearSubscriptions();

Get following error:
Cannot read property 'size' of undefined
at Eth.RequestManager.clearSubscriptions (node_modules/web3-core-requestmanager/src/index.js:266:28)

web3 1.2.7
ts-node 8.7.0
node 10.18.0