Executing "Usage Example" => Error: No dat here

Do I need to pass in a leveldb?
The readme says something about

(default is require('leveldown'))

I do

var dat = require('dat-core')

var db = dat('./test')

db.put('hello', 'world', function (err) { // insert value 
  if (err) return handle(err) // something went wrong 
  db.get('hello', function (err, result) {
    if (err) return handle(err) // something went wrong 
    console.log(result)   // prints result 
    console.log(db.head) // the 'head' of the database graph (a hash) 
  })
})

// function handle (err) { console.error(err); }

and get

events.js:141
      throw er; // Unhandled 'error' event
            ^
Error: No dat here
    at /home/serapath/EXPERIMENTS/DAT_CORE/node_modules/dat-core/index.js:213:44
    at FSReqWrap.cb [as oncomplete] (fs.js:212:19)

Reproduce the README's "Usage Example" using the shown dat-core code and inspect node_modules/dat-core/index.js around line 213, where the "No dat here" error is raised. Determine whether the example requires a LevelDB setup or has incorrect documentation, then verify that the documented example runs without the unhandled error.