title: poetry Virtual environment already activated
body: <p>Running the following</p>
  
  <pre><code>poetry shell
  </code></pre>
  
  <p>returns the following error</p>
  
  <pre><code>/home/harshagoli/.poetry/lib/poetry/_vendor/py2.7/subprocess32.py:149: RuntimeWarning: The _posixsubprocess module is not being used. Child process reliability may suffer if your program uses threads.                                                                                                                                                                                    
    "program uses threads.", RuntimeWarning)                                                                                                                                                    
  The currently activated Python version 2.7.17 is not supported by the project (^3.7).                                                                                                         
  Trying to find and use a compatible version.                                                                                                                                                  
  Using python3 (3.7.5)                                                                                                                                                                         
  Virtual environment already activated: /home/harshagoli/.cache/pypoetry/virtualenvs/my-project-0wt3KWFj-py3.7
  </code></pre>
  
  <p>How can I get past this error? Why doesn't this command work?</p>