title: Vim format Python code with Black and then force tabs
body: <p>I'm using the <a href="https://github.com/dense-analysis/ale" rel="nofollow noreferrer">ALE plugin</a> to format Python code with <a href="https://github.com/psf/black" rel="nofollow noreferrer">Black</a>. Black indents the file with spaces (it's the same case with AutoPep8), but I want to keep my tabs. So I wrote this keybinding to run Black then swap spaces with tabs:</p>
  <pre><code>nnoremap &lt;leader&gt;ff :ALEFix&lt;cr&gt;:%retab!&lt;cr&gt;
  </code></pre>
  <p>When I run this, it works, but when I run it again the spaces stay there, and when I run it again it works, and so on. I works for one time, does not for the next, and so on...</p>
  <p>I tried this as well, but got the same result:</p>
  <pre><code>nnoremap &lt;leader&gt;ff :ALEFix&lt;cr&gt;gg=G
  </code></pre>
  <p>What should I do so that it always runs correctly, runs Black, then always returns back my tabs?</p>