old_contents: 
  var hash = require('../')
  var pull = require('pull-stream')
  require('tape')('abc', function (t) {
  pull.values(['a', 'b', 'c'])
    .pipe(hash(function (err, sum) {
      if(err) throw err
      console.log(sum)
      t.equals(sum, 'a9993e364706816aba3e25717850c26c9cd0d89d')
      t.end()
    }))
  
  })
  
new_contents: 
  var hash = require('../')
  var pull = require('pull-stream')
  require('tape')('abc', function (t) {
  pull(
    pull.values(['a', 'b', 'c']),
    hash(function (err, sum) {
      if(err) throw err
      console.log(sum)
      t.equals(sum, 'a9993e364706816aba3e25717850c26c9cd0d89d')
      t.end()
    })
  )
  
  })
  
subject: update to new style