title: In requests_cache, does the sqlite file contain the cached request time and age?
body: <p>Consider the following code:</p>
  
  <pre><code>import requests
  import requests_cache
  
  requests_cache.install_cache(expire_after=7200)
  
  url = 'http://www.example.com'
  with requests.Session() as sess:
      response = sess.get(url)
      print response.text
  </code></pre>
  
  <h2>First run</h2>
  
  <p>When I first run this code, I am sure that the <code>GET</code> request is sent out to <code>www.example.com</code>, since no cache has been set up yet.  I will then see a file named <code>cache.sqlite</code> in the working directory, which contains the request being cached inside it.</p>
  
  <h2>The first process will then exit, erasing all traces of it from RAM.</h2>
  
  <h2>Second run, maybe 2000 seconds later</h2>
  
  <p>What else does <code>requests_cache.install_cache</code> do? Aside from "installing" a cache, does it also tell the present Python session that "Hey, there's a cache present right now, you might want to look into it before sending out new <code>requests</code>".</p>
  
  <p>So, my question is, does the new instance of my script process respect the existing <code>cache.sqlite</code> or does it create an entirely new one from scratch?</p>
  
  <p>If not, how do I make sure that it will look up the existing cache first before sending out new <code>requests</code>, and also consider the age of the cached requests?</p>