title: No module named 'virtualenv'
body: <p>I installed 'virtualenv' with</p>
  
  <pre><code>pip install virtualenv
  </code></pre>
  
  <p>Installing collected packages: virtualenv</p>
  
  <p>Successfully installed virtualenv-16.0.0</p>
  
  <p>However, when I run 'virtualenv  project1' it gives me this error:</p>
  
  <pre><code>**ModuleNotFoundError: No module named 'virtualenv'**
  </code></pre>
  
  <p>It happens with every package I tried to install. I have python2 and python3 at the same time. I suspect that is messing up everything. Does anyone know how to fix this?</p>