title: Is there any use in importing both ES6 and ES7 core-js polyfills?
body: <p>Is it useful or redundant to import the ES6 polyfill for <code>Object</code></p>
  
  <pre><code>import 'core-js/es6/object';
  </code></pre>
  
  <p>and also the ES7 polyfill for <code>Object</code>?</p>
  
  <pre><code>import 'core-js/es7/object';
  </code></pre>
  
  <p>Does the ES7 polyfill cover all of the ES6 features and can I leave the ES6 polyfill out, or does the ES6 polyfill add features not present in the ES7 polyfill?</p>