title: ImportError: cannot import name 'safe_str_cmp' from 'werkzeug.security'
body: <p>Any ideas on why I get this error?</p>
  <p>My project was working fine. I copied it to an external drive and onto my laptop to work on the road; it worked fine. I copied it back to my desktop and had a load of issues with invalid interpreters etc, so I made a new project and copied just the scripts in, made a new requirements.txt and installed all the packages, but when I run it, I get this error:</p>
  <pre><code>Traceback (most recent call last):
    File &quot;E:\Dev\spot_new\flask_blog\run.py&quot;, line 1, in &lt;module&gt;
      from flaskblog import app
    File &quot;E:\Dev\spot_new\flask_blog\flaskblog\__init__.py&quot;, line 3, in &lt;module&gt;
      from flask_bcrypt import Bcrypt
    File &quot;E:\Dev\spot_new\venv\lib\site-packages\flask_bcrypt.py&quot;, line 21, in &lt;module&gt;
      from werkzeug.security import safe_str_cmp
  ImportError: cannot import name 'safe_str_cmp' from 'werkzeug.security' (E:\Dev\spot_new\venv\lib\site-packages\werkzeug\security.py)
  </code></pre>
  <p>I've tried uninstalling Python, Anaconda, PyCharm, deleting every reg key and environment variable I can find that looks pythonic, reinstalling all from scratch but still no dice.</p>