title: How to install old version of library in Pip3
body: <p>I would like to use <code>opencv-python</code> and <code>opencv-contrib-python</code> versions in 3.3 or below on Python 3.7. The issue is that I can't seem to get them on <code>pip3</code>. I need it to be <code>pip3</code> and <code>Python 3.7</code> because it's to run on Google Cloud Functions.</p>
  
  <p>If I run <code>$ pip3 install opencv-contrib-python==</code> to get the versions I get:</p>
  
  <pre><code>versions: 3.4.2.16, 3.4.2.17, 3.4.3.18, 3.4.4.19, 3.4.5.20, 4.0.0.21, 4.0.1.24, 4.1.0.25
  </code></pre>
  
  <p>and from <code>pip3 install opencv-python==</code></p>
  
  <pre><code>versions: 3.4.2.16, 3.4.2.17, 3.4.3.18, 3.4.4.19, 3.4.5.20, 4.0.0.21, 4.0.1.24, 4.1.0.25
  </code></pre>
  
  <p>How can I get older versions like 3.3.1.11 which are available in <code>pip2</code>?</p>
  
  <p>Of course deploying trying to get the old version on <code>GCloud</code> gives me</p>
  
  <pre><code>ERROR: (gcloud.functions.deploy) OperationError: code=3, message=Build failed: {"error": {"canonicalCode": "INVALID_ARGUMENT", "errorMessage": "`pip_download_wheels` had stderr output:\n  Could not find a version that satisfies the requirement opencv-python==3.2.0.7 (from -r requirements.txt (line 2)) (from versions: 3.4.2.17, 3.4.3.18, 3.4.4.19, 3.4.5.20, 4.0.0.21, 4.0.1.23, 4.0.1.24, 4.1.0.25)\nNo matching distribution found for opencv-python==3.2.0.7 (from -r requirements.txt (line 2))\n\nerror: `pip_download_wheels` returned code: 1", "errorType": "InternalError", "errorId": "91F6A3AC"}}
  </code></pre>