title: Python Error: ModuleNotFoundError: No module named 'cryptography.hazmat.bindings._constant_time'
body: <p>I'm trying to run a script that I've been able to run in the past.  It stops with error:</p>
  
  <pre><code>ModuleNotFoundError: No module named 'cryptography.hazmat.bindings._constant_time'
  </code></pre>
  
  <p>I recently removed python 3.6 and installed python ActiveState:</p>
  
  <pre><code>ActivePython 3.6.0.3600 (ActiveState Software Inc.) based on
  Python 3.6.0 (default, Jan 23 2017, 20:01:14) [MSC v.1900 64 bit (AMD64)] on win32
  </code></pre>
  
  <p>Things I've tried thus far:</p>
  
  <p>Re-installing cryptography</p>
  
  <p>Re-installing cryptography but I get an error:</p>
  
  <pre><code>Program Files (x86)\Windows Kits\10\include\10.0.17763.0\shared" "-IC:\Program Files (x86)\Windows Kits\10\include\10.0.17763.0\um" "-IC:\Program Files (x86)\Windows Kits\10\includ
  e\10.0.17763.0\winrt" "-IC:\Program Files (x86)\Windows Kits\10\include\10.0.17763.0\ucrt" "-IC:\Program Files (x86)\Windows Kits\NETFXSDK\4.6.1\include\um" /Tcbuild\temp.win-amd64
  -3.6\Release\_openssl.c /Fobuild\temp.win-amd64-3.6\Release\build\temp.win-amd64-3.6\Release\_openssl.obj
    error: command 'cl.exe' failed: No such file or directory
  
    ----------------------------------------
    Failed building wheel for cryptography
    Running setup.py clean for cryptography
  Failed to build cryptography
  Could not build wheels for cryptography which use PEP 517 and cannot be installed directly
  </code></pre>
  
  <p>Any help would be much appreciated.  I'm fairly new to python but I'm at a loss</p>