title: What is the equivalent to $HOME in a virtualenv (python) - specifically for matplotlibrc
body: <p>I have found this beautiful <a href="http://www.huyng.com/posts/sane-color-scheme-for-matplotlib/">ggplot inspired color scheme for matplotlib</a> and want to use it for a specific project.</p>
  
  <p>As per the matplotlib documentation, custom color scheme should not overwrite the default in <code>site-packages</code> but instead be placed in <code>$HOME/.matplotlib</code>. But what is the equivalent for <code>$HOME</code>in a <code>venv</code>? Specifically: how can I make sure this color scheme is not overwritten when installing/upgrading a new <code>matplotlib</code></p>