title: How to fix 'ImportError: No module named pssevrsn'
body: <p>Try to use python to call psse. but something wrong with importing dyntools.</p>
  
  <pre class="lang-py prettyprint-override"><code>from __future__ import division
  
  import os, sys, math, csv, time
  PSSPY_location = r'C:\Program Files (x86)\PTI\PSSE34\PSSPY27'
  PSSE_location = r'C:\Program Files (x86)\PTI\PSSE34\PSSBIN'
  sys.path.append(PSSPY_location)
  os.environ['PATH'] += ';' + PSSPY_location
  os.environ['PATH'] += ';' + PSSE_location
  
  import socket
  import struct
  import numpy, copy
  
  import initialize_mute as mt    # mute all psse outputs
  # import psse34
  import dyntools
  import psspy
  import redirect
  </code></pre>
  
  <pre><code>import dyntools
    File ".\dyntools.py", line 51, in &lt;module&gt;
  ImportError: No module named pssevrsn
  </code></pre>
  
  <p>Process finished with exit code 1</p>