title: RequestParser.parse_args() not recognizing arguments
body: <p>I'm creating a REST API with flask_restful and want to parse the arguments coming from a PUT request. Below is the relevant code:</p>
  <pre><code>user_put_args = reqparse.RequestParser()
  user_put_args.add_argument(&quot;user_id&quot;, type=&quot;str&quot;, help=&quot;user_id is needed for this user&quot;)
  user_put_args.add_argument(&quot;spotify_username&quot;, type=&quot;str&quot;, help=&quot;Spotify username for the corresponding user_id&quot;)
  user_put_args.add_argument(&quot;apple_music_username&quot;, type=&quot;str&quot;, help=&quot;Apple Music username for the corresponding user_id&quot;)
  </code></pre>
  <p>PUT function declaration:</p>
  <pre><code>def put(self, user_id):
     args = user_put_args.parse_args()
     rest of code ...
  </code></pre>
  <p>and here's the put request:</p>
  <pre><code>req4 = requests.put(HEROKU_BASE + &quot;/users/&quot; + &quot;test1&quot;, {&quot;spotify_username&quot;: &quot;test_1&quot;, &quot;apple_music_username&quot;:&quot;something&quot;})
  print(req4.json())
  </code></pre>
  <p>The response I'm getting from the put call is:</p>
  <pre><code>{'message': {'spotify_username': 'Spotify username for the corresponding user_id'}}
  </code></pre>
  <p>meaning it's getting hung up on the request parse.</p>
  <p>Any ideas on how to fix this? I'm following a guide that led me to this and my code is almost exactly the same. Thanks!</p>