title: How to Install a python package via pip in site-packages of specific python installation?
body: <p>When I run <code>pip install fasteners</code>, it shows</p>
  <pre><code>Defaulting to user installation because normal site-packages is not writeable
  Requirement already satisfied: fasteners in ./.local/lib/python3.6/site-packages (0.15)
  Requirement already satisfied: six in ./.local/lib/python3.6/site-packages (from fasteners) (1.15.0)
  Requirement already satisfied: monotonic&gt;=0.1 in ./.local/lib/python3.6/site-packages (from fasteners) (1.5)
  </code></pre>
  <p>The package is installed in <strong><code>./.local/lib/python3.6/site-packages</code></strong>.</p>
  <p>But I want to install it in <code>/usr/bin/python2/site-packages</code> ,</p>
  <p>because <code>duplicity</code> uses python2 . And on running <code>duplicity --version</code> i get <code>could not import fasteners</code> error</p>