title: Assign variable to 'import'ed ES2015 module
body: <p>Let's say I have module like this,</p>
  
  <pre><code>//mul.js
  export default function (v) {
    return v * v;
  }
  </code></pre>
  
  <p>use like follows.</p>
  
  <pre><code>import mul from 'mul.js'
  console.log(mul(3))
  </code></pre>
  
  <p>The question is, how can I assign module <code>mul</code> to another variable(or object)? I don't want to pollute namespace for every modules.</p>