title: ModuleNotFoundError: No module named 'google_auth_oauthlib'
body: <p>I am trying to run the 'generate_refresh_token.py' file in the authentification folder of the AdWords API.</p>
  <p>But when I do <code>python generate_refresh_token.py</code> as described in the <a href="https://github.com/googleads/googleads-python-lib/wiki/API-access-using-own-credentials-(installed-application-flow)#step-2---setting-up-the-client-library" rel="noreferrer">documentation</a>, I get the error <code>ModuleNotFoundError: No module named 'google_auth_oauthlib'</code>.</p>
  <p>So I try to install the module with <code>pip install google-auth-oauthlib</code>, and here is the output:</p>
  <pre><code>Requirement already satisfied: google-auth-oauthlib in /home/$USER/anaconda3/lib/python3.6/site-packages (0.2.0)
  </code></pre>
  <p>I activate my anaconda3 environment by doing <code>source activate /home/$USER/anaconda3/envs/$environment_name</code>. I try to generate the token again with the command above, same error.</p>
  <p>Could not find any useful answer or anyone having the same issue with this module. Does anyone have a suggestion I could try?</p>
  <p>UPDATE: I have found the error. When I installed the google-auth-oauthlib module via pip, it was installed as a module in the anaconda3 library. But when I run python from the command line, it uses the version from my system, which doesn't have this module.</p>