title: How to import "psutil"
body: <p>I am trying to import and use <code>psutil</code> from within a python-script (<code>.py</code> file).</p>
  <p>This <code>.py</code> file is part of a <code>juju-charm</code> layer. To be specific, it is a <code>command</code> script for collecting <code>metrics</code> from the machine running the <code>charm-application</code>:</p>
  <pre><code>#!/usr/bin/env python3
  
  import psutil
  
  if __name__ == '__main__':
    cpu_times = psutil.cpu_times(percpu=False)
    print(cpu_times )
  </code></pre>
  <p>Now when I build the <code>charm-layer</code> and deploy it using <code>juju</code>, I get the following error:</p>
  <blockquote>
  <p>ImportError: No module named psutil</p>
  </blockquote>
  <p>This means that the machine (which was brought up by <code>juju</code>) called and invoked that <code>.py</code> file successfully. But failed to import <code>psutil</code>.</p>
  <p>My question is how to import <code>psutil</code> successfully?</p>
  <p>(I will highly appreciate a <code>juju-charm</code> related answer if there is any but it is not necessary)</p>