title: Google Adword API generate refresh token using generate_refresh_token.py
body: <p>I follow the step here:
  <a href="https://github.com/googleads/googleads-python-lib/wiki/Using-OAuth-2.0" rel="nofollow">https://github.com/googleads/googleads-python-lib/wiki/Using-OAuth-2.0</a></p>
  
  <ol>
  <li>Log in google developers console</li>
  <li>Create project, then credentials, then acquired the client ID and client secret</li>
  <li>Install the googleads through pip and download the library: <a href="https://github.com/googleads/googleads-python-lib" rel="nofollow">https://github.com/googleads/googleads-python-lib</a></li>
  <li><p>Put in client ID and client secret in this example file: <a href="https://github.com/googleads/googleads-python-lib/blob/master/examples/adwords/authentication/generate_refresh_token.py" rel="nofollow">https://github.com/googleads/googleads-python-lib/blob/master/examples/adwords/authentication/generate_refresh_token.py</a></p>
  
  <p>CLIENT_ID = 'xxxxxxx.apps.googleusercontent.com'</p>
  
  <p>CLIENT_SECRET = 'xxxxxxxxxxxxxxxxx'</p></li>
  <li><p>Then I run the generate_refresh_token.py</p></li>
  </ol>
  
  <p>And I got the following error message:</p>
  
  <pre><code>raise AttributeError('No client_id or client_secret specified.')
  AttributeError: No client_id or client_secret specified.
  </code></pre>
  
  <p>I'm really new to this and please tell me what I missed. Thanks </p>