title: Why isn't my Python package found when I attempt to install it?
body: <p>I have tried installing the package invasion_PGF but constantly get the error messages:</p>
  <blockquote>
  <p>Could not find a version that satisfies the requirement invasion_PGF (from versions: none)</p>
  </blockquote>
  <p>and</p>
  <blockquote>
  <p>No matching distribution found for invasion_PGF.</p>
  </blockquote>
  <p>I was installing using the command: <code>pip install invasion_PGF</code> in the Anaconda command prompt.</p>
  <p>Can someone help me with ideas on how to deal with this?</p>