title: How to install pip3 for a specific python version
body: <p>I have python3.7 installed but also python3.4. For example:</p>
  
  <pre><code>$ python3
  Python 3.4.3 (default, Nov 12 2018, 22:25:49) 
  [GCC 4.8.4] on linux
  Type "help", "copyright", "credits" or "license" for more information.
  </code></pre>
  
  <p>And:</p>
  
  <pre><code>$ python3.7
  Python 3.7.0 (default, Jun 28 2018, 00:00:00) 
  [GCC 4.8.4] on linux
  Type "help", "copyright", "credits" or "license" for more information.
  </code></pre>
  
  <p>How can I install packages to <code>python3.7</code> ? Any <code>pip3</code> command I use goes to python3.4 and I'm not sure how to install anything for python3.7. Any ideas? Even running something like this doesn't work:</p>
  
  <pre><code>$ python3.7 -m ensurepip --upgrade
  /usr/bin/python3.7: No module named ensurepip
  </code></pre>
  
  <p>Or:</p>
  
  <pre><code>$ sudo python3.7 -m pip install PyMySQL
      register_loader_type(importlib_bootstrap.SourceFileLoader, DefaultProvider)
  AttributeError: module 'importlib._bootstrap' has no attribute 'SourceFileLoader'
  </code></pre>