title: how to correctly use format string python
body: <p>I'm trying to use the format string from python with this.</p>
  <pre><code>values = f'''{
            &quot;sourceId&quot;: &quot;{merchant['siteId']}&quot;,
            &quot;programId&quot;: &quot;{merchant['id']}&quot;
          }'''
  </code></pre>
  <p>but I'm getting invalid format specifier.
  any idea how to use it correctly in this situation?</p>