title: get_or_create in Peewee
body: <p>The paragraph titled <a href="http://peewee.readthedocs.io/en/latest/peewee/querying.html#create-or-get" rel="nofollow">Get or create</a> on the peewee documentation says:</p>
  
  <blockquote>
    <p>While peewee has a <code>get_or_create()</code> method, this should really not be
    used outside of tests as it is vulnerable to a race condition. The
    proper way to perform a <em>get</em> or <em>create</em> with peewee is to rely on the
    database to enforce a constraint.</p>
  </blockquote>
  
  <p>And then it goes on with an example that only shows the create part, not the get part.</p>
  
  <p>What is the best way to perform a get or create with peewee?</p>