Stubbing single exported function with Sinon

I have just changed my lodash import from import _ from 'lodash'; to import debounce from 'lodash/debounce';
In my test I used to have sandbox.stub(_, 'debounce').returnsArg(0);, but now I'm stuck as to what to change it to. Obviously sandbox.stub(debounce).returnsArg(0); won't work. Not sure what to do when only a single function is exported from a module.