title: Leave Non-Declared Arguments to Their Default Values
body: <p>I am creating a RESTful API using Flask and Flask-Restful and am running into a problem with PUT requests and the arguments. I have a JSON file that contains:</p>
  
  <pre><code>{
      "checked": 1465628401,
      "number": 21600,
  }
  </code></pre>
  
  <p>When the user sends <code>"/api/v1/status?checked=10"</code> it changes the checked value like it should but sets <em>number</em> to null. I'm wondering if there is a way I can have it so that if a user does not specify that argument, it stays as its current value.</p>
  
  <p>Right now, I define my RequestParser like:</p>
  
  <pre><code>parser = reqparse.RequestParser()
  </code></pre>
  
  <p>And add each argument like:</p>
  
  <pre><code>parser_status.add_argument('checked', type=int)
  parser_status.add_argument('number', type=int)
  </code></pre>
  
  <p>So my question is, is there a way to default each JSON key to stay as its current value unless the argument is present in the PUT request?</p>
  
  <p>The documentation states: <em>Also note: Arguments declared in your request parser but not set in the request itself will default to None.</em> Im wondering if there is a way to change that default.</p>