title: cairocffi install failed on Ubuntu 18.04
body: <p>I am running <code>pip freeze</code> on a python project, it shows string VERSION other than numberical version and it fails the package installation, the warning message is:</p>
  
  <blockquote>
    <p>weasyprint 43 has requirement cairocffi>=0.9.0, but you'll have cairocffi file-.cairocffi-VERSION which is incompatible.</p>
  </blockquote>
  
  <pre><code>cairocffi===file-.cairocffi-VERSION
  </code></pre>
  
  <p>cairoccffi is a dependency of Weasyprint which i use in my project and weasypring version is correct:</p>
  
  <pre><code>WeasyPrint==43
  </code></pre>
  
  <p>I tried using <code>pipreqs</code> generates requirements.txt, it didn't show cairocffi package but the package installation fails with the same error.</p>
  
  <p>I checked site-packages folder, it contains</p>
  
  <pre><code>cairocffi-file_.cairocffi_VERSION.dist-info/
  </code></pre>
  
  <p>which cause the issue.</p>
  
  <p>Can someone help? </p>