title: openapi 3.0 specify complex filter in parameters
body: <p>I have an api to specify in openapi 3.0 (.yml)</p>
  <p>I struggle with specifying an optional filter parameter. Especially with dynamic keys for featureId. I looked at: <a href="https://swagger.io/docs/specification/data-models/dictionaries/" rel="nofollow noreferrer">https://swagger.io/docs/specification/data-models/dictionaries/</a></p>
  <p>featureId's look like this: dws33231j
  The amount of featureId objects can vary</p>
  <p>My Data structure:</p>
  <pre><code>    [
          &quot;featureId1&quot; =&gt; [
              &quot;selectedOption1&quot;,
              &quot;selectedOption2&quot;
          ],
          &quot;featureId2&quot; =&gt; [
              &quot;selectedOption8&quot;
          ],
          ...
      ]
  </code></pre>
  <p>curl should look like this: https://path/articles&amp;filter[featureId1]=selectedOption1,selectedOption2,selectedOption6&amp;filter[featureId2]=selectedOption8'</p>
  <p>So far i have this, that is far from right. How do I specify dynamic keys?</p>
  <pre><code>components:
    parameters:
      filter:
        name: filter
        in: query
        style: deepObject
        allowReserved: true
        description: 
        schema:
          $ref: &quot;#/components/schemas/filter&quot;
  
    schemas:
      filter:
        type: object
        properties:
          featureId1:
            description: id of the feature
            type: array
            items: 
              type: string
              example: [selectedOption1, selectedOption2, selectedOption6]
  </code></pre>