title: Is there an object that compares smaller than any valid datetime.datetime(...)?
body: <p>Is there a <code>MIN</code> constant for <code>datetime</code>?</p>
  
  <p>I need it to represent the expiration date of a resource, and I want to have a <code>datetime</code> that represents "always expires" as default value (instead of <code>None</code> so I can use the same expiration comparison no matter what). </p>
  
  <p>So right now I'm using <code>datetime.datetime(datetime.MINYEAR,1,1,0,0,tzusc())</code> as my  <code>MIN datetime</code> but I wonder if there is some other way to represents "the lowest possible time" (even if it's not a <code>datetime</code>). </p>